Description of the proposeD expansion 5...90 Olympic Dam Expansion Draft Environmental Impact Statement 2009 Coastal desalination plant (Section 5.7.4) Water supply pipeline (Section

Olympic Dam Expansion Draft Environmental Impact Statement 2009 89

5Description of the proposeD expansion 5

5.1 introDuctionThis chapter describes the various phases and timing for the

development of the proposed expansion. It provides a holistic

overview of the expansion, before describing each of the major

components: mining, processing, waste management, water

supply, electricity supply, transportation, workforce and

accommodation. A brief context and overview is provided for

each component, followed by details of the proposed design,

construction method and operation. Strategies for the

progressive rehabilitation and future closure are presented in

Chapter 23, Rehabilitation and Closure.

The proposed expansion is scheduled to start immediately

following approval by the Australian, South Australian and

Northern Territory governments and a decision by the Board of

BHP Billiton Group to proceed. The proposed expansion would

increase total production at Olympic Dam from the current

nameplate capacity of 235,000 tonnes per annum (tpa) of

copper plus associated products (i.e. uranium oxide, gold and

silver) to up to 750,000 tpa of refined copper equivalent plus

associated products.

5.2 expansion overviewThe proposed expansion introduces a new open pit mining

operation, together with an increased capacity to process

minerals and additional infrastructure to support the expanded

operation (see Figure 5.1).

Table 5.1 provides an overview of the indicative ore, mine rock

and metal production rates for the proposed expansion. A

summary of the major inputs and outputs is also provided in

Figure 5.2.

About 300–350 m of overburden would be removed over a

period of five to six years to reach the ore. Once ore has been

reached, the mining rate would be progressively increased from

an initial rate of 20 Mtpa to about 60 Mtpa of ore. The mined

ore would be sent to both the existing and a new metallurgical

plant for processing. An additional 350–390 Mtpa of mine rock

would also be extracted. The mine rock comprises overburden

and mineralised rock that is currently uneconomic to process,

and this material would be directed to the rock storage facility

(RSF) or low-grade stockpiles for future processing.

table 5.1 indicative ore, mine rock and metal production rates

production measure current operation (post-optimisation)1

proposed expansion combined operations

Ore mined (Mtpa) 12 60 72

Mine rock (Mtpa) 0 350–390 350–390

Total material movement (Mtpa) 12 410 422

Copper concentrate (ktpa) 600 1,800 2,400

Refined copper (ktpa) 235 5152 7502

Uranium oxide (tpa) 4,500 14,5002 19,0002

Gold bullion (oz/a) 100,000 700,0002 800,0002

Silver bullion (oz/a) 800,000 2,100,0002 2,900,0002

1 Nameplate capacity.2 Includes on-site and overseas production.

Olympic Dam Expansion Draft Environmental Impact Statement 200990

Coastaldesalination

plant(Section 5.7.4)

Water supplypipeline

(Section 5.7.5)

Electricitytransmission

line(Section 5.8.3)

On-sitecombined cycle

gas turbineelectricity

generation(Section 5.8.5)

On-sitecogeneration

plant(Section 5.8.7)

Outer Harbor(Section 5.9.5)

Landing facility(Section 5.9.5)

Accommodation(Section 5.10.2)

Airport(Section 5.9.6)

Local salinewellfields

(Section 5.7.7)

NationalElectricity

Market(Section 5.8.2)

Gas pipelinefrom

Moomba(Section 5.8.6)

Waste heatfrom sulphur

burning(Section 5.5.4)

Materialsrequired

(Sections 5.4.5and 5.5.5)

Workforce(Section 5.10.1)

Expanded operation

Open pit mine(Section 5.4)

Metallurgical plant(Section 5.5)

Outer Harbor andPort of Darwin(Section 5.9.5)

Airport(Section 5.9.6)

Rock storagefacility

(Section 5.4.6)

Proposed operation

Outputs

Inputs

OreRefined copper

Export concentrateUranium oxide

Gold and silver bullion

Tailings storagefacility

(Section 5.5.6)

Road / rail transport(Sections 5.9.2,5.4.3 and 5.9.4)

Figure 5.1 Expansion overview

Olym

pic Dam

Expansion Draft Environm

ental Impact Statem

ent 200991

5

Rock storage facility(350 Mtpa mine rock)

Note: Water and electricity demand amounts are for the combined (existing and proposed) on site operation and exclude off-site infrastructure and some on-site demands including administration facilities and processing infrastructure.

Copper anode(330,000 tpa)

Water: 96 ML/dElectricity: 2,652 GWh/annum

Water: 7.5 ML/dElectricity: 244 GWh/annum

Electricity: 689 GWh/annumWater: 43 ML/d

Electricity: 95 GWh/annumWater: 0.3 ML/d

Water: 30 ML/dElectricity: 453 GWh/annum Uranium-rich

tailings(69.6 Mtpa)

Copper electrolyte(3.6 ML/d)

Copper-rich concentrate(0.8 Mtpa)

Ore(72 Mtpa)

Uranium oxide(17,000 tpa)

Concentrate(1.6 Mtpa)(containing about400,000 tpa copper,2,000 tpa uranium oxide,1,900,000 oz silver and530,000 oz gold)

Copper cathode(350,000 tpa)

Silver (1,000,000 oz)Gold (270,000 oz)

Tailings storage facility(69.6 Mtpa tailings)

OPE

N P

IT A

ND UNDERGROUND M

INE

CONCENTRATOR

HYD

ROMETALLURGICAL PLA

NT

SM

ELTER AND ACID PLANT

REFINERY

ORE PROCESSINGMINING

Figure 5.2 Combined operations overview and key inputs and outputs


The metallurgical plant and tailings storage facility (TSF) would

be expanded to accommodate the increased ore throughput.

A new concentrator and hydrometallurgical facility would be

constructed, and the existing copper solvent extraction, smelter

and refinery would be modified and optimised to process

approximately 800,000 tpa of copper concentrate sourced from

both the existing and expanded operation (termed the

combined operations). This would produce approximately

350,000 tpa of refined copper at Olympic Dam. A further

1.6 Mtpa of copper concentrate containing recoverable

quantities of uranium oxide, gold and silver (hereafter called

concentrate) would be produced within the new concentrator

facility. This would be exported via the Port of Darwin to an

overseas hydrometallurgical and smelting facility. The total

on-site ore throughput would be equivalent to about 750,000

tpa of refined copper from the combined operations.

The new open pit mine and metallurgical plant would require

material inputs which exceed the capacity of the current water,

electricity and workforce infrastructure (see Table 5.2). As a

result, new infrastructure would be required.

The main components of additional infrastructure required to

support the proposed mining and metallurgical expansion are:

a desalination plant located at Point Lowly, and a 320 km •

water supply pipeline between the proposed desalination

plant and Olympic Dam

the option of a 270 km, 275 kV transmission line from Port •

Augusta to Olympic Dam, or an on-site 600 MW capacity

combined cycle gas turbine (CCGT) power station to be fed

from a gas pipeline from Moomba, or a hybrid solution

involving both options

a new 105 km rail spur between Pimba and Olympic Dam•

a landing facility located about 10 km south of Port Augusta •

to offload pre-assembled and prefabricated infrastructure

a new access corridor from the landing facility to the Port •

Augusta pre-assembly yard and on to the Stuart Highway

a new rail/road intermodal freight terminal to be constructed •

at Pimba

a new workers’ accommodation village (Hiltaba Village) to •

be located between Roxby Downs and Andamooka to

replace the existing Olympic Village

a new airport to be located adjacent to the proposed Hiltaba •

Village to replace the existing airport at Olympic Dam

Village

the expansion of Roxby Downs township, including •

residential, commercial and retail areas

a new heavy industrial area to replace the existing Olympic •

Dam Village heavy industrial area in Charlton Road

the development of a saline groundwater supply principally •

for dust suppression

the development of port facilities at Outer Harbor to import •

sulphur and other mining and metallurgical reagents and

export additional refined copper and uranium oxide

the development of port facilities at the Port of Darwin, •

East Arm, for the export of concentrate and additional

uranium oxide

the relocation and expansion of the existing on-site •

desalination plant

the relocation of Borefield Road.•

Figures 5.3 and 5.4 show the proposed major infrastructure

elements in the regional context, and Figure 5.5 illustrates the

elements in the local context of Olympic Dam. The development

of the proposed mining and processing operation at Years 5, 10,

20 and 40 are shown in Figure 5.6a and b.

table 5.2 indicative major infrastructure demands

expansion requirement current operation proposed expansion combined operations

Water demand (average GL per annum/ML per day) 13/371 70/1831 83/2201

Electricity consumption (MWh per annum) 870,000 4,400,000 5,270,000

Diesel usage (ML per annum) 26 403 429

Peak construction/shutdown workforce 1,400 6,000 1,400

Ongoing operational workforce 4,150 4,000 8,000

Sulphur usage (tpa) 80,000 1,720,000 1,800,000

1 Excludes additional water demand from off-site infrastructure.

Olym

pic Dam


ental Impact Statem

ent 200993

5

Andamooka

Roxby Downs

OLYMPICDAM

LakeTorrens

Lyndhurst

Marree

Moomba

LakeEyre North

LakeEyre South

LakeBlanche

LakeGregory

LakeCallabonna

kp80

kp60

kp40

kp20

kp440

kp420

kp400

kp380

kp360

kp340

kp320

kp300

kp280

kp260kp240kp220

kp560

kp540

kp520

kp500

kp480

kp460

kp440

kp420

kp400kp380

kp360kp340

kp320

kp300

kp280

kp260kp240kp220

kp200

kp180

kp160

kp140

kp120

kp100

0 10 20 30 40 50km

Kilometre point (kp)

Existing compressor station

Existing major roads

Existing gas pipeline

Gas pipeline alignment options

Expanded Special Mining Lease

Existing Olympic Dam Special Mining Lease

Existing Roxby Downs Municipality

EIS Study Area

Moomba

Whyalla

Adelaide

Port Pirie

Roxby Downs

Port Augusta

OLYMPICDAM Andamooka

Moomba

Gas pipeline alignment optionsOption 1


MoombaOption 2


MoombaOption 3

Figure 5.3 Major infrastructure elements of the proposed expansion within the gas pipeline corridor options


IslandLagoon

Lake Torrens

PernattyLagoon

LakeWindabout

Pimba

Whyalla

Andamooka

Roxby Downs

Port Augusta

Woomera

PointLowly

OLYMPICDAM

LakeTorrens

Pre-assemblyyard

kp80

kp60

kp40

kp20

kp320

kp300

kp280

kp260

kp240

kp220

kp200

kp180

kp160

kp140

kp120

kp100

See inset 2

0 10 20 30 40 50km


Landing facility

Desalination plant

Existing railway

Existing major roads


Water pipeline alignment

Adjacent Olympic Dam - SA Governmentwater pipeline alignments

Transmission line alignments

Rail alignment

Access corridor




EIS Study Area

Preferred intake pipe alignment

Preferred outfall pipe alignment

Santosfacilities

Inset 2Desalination plant

Rock pad(below water level)

Offloading wharf

Customs and quarantinelaydown area

Access corridor

Berthingdolphin

Inset 1Landing facility

See inset 1

Moomba

Whyalla

Adelaide

Port Pirie

Roxby Downs

Proposeddesalination plant

0 0.1 0.2km

0 0.5 1km

Pumpstation

Port Augusta

Figure 5.4 Components of the proposed expansion in the southern corridor

Olym

pic Dam


ental Impact Statem

ent 200995

5

Tailings storage facility(at 40 years)


(at 40 years)

Open pit(at 40 years)

HiltabaVillage

Relocated andexpanded airport

Extent oftownshipexpansion

Arid Recovery

Relocated Borefield Road

Mine maintenenceindustrial area

Roxby Downs

Heavy industrialarea

Balance ponds Low gradeore stockpile(at 40 years)

Camp 2(temporary)

Metallurgical plant

Hiltaba - Roxby Downs sewer alignment



Rail alignment

Transmission line alignment

Arid Recovery




EIS Study Area0 1 2 3 4 5

km

Explosives storagefacility

Figure 5.5 Major components of the proposed expansion around Olympic Dam


AT 5 YEARS

AT 10 YEARS


Openpit

Metallurgicalplant

HiltabaVillage Airport

Roxby Downs


Figure 5.6a Conceptual development of the proposed expansion


5

AT 20 YEARS

AT 40 YEARS


Openpit

Metallurgicalplant


HiltabaVillage Airport

Roxby Downs

Figure 5.6b Conceptual development of the proposed expansion


5.3 expansion staging anD timingThe proposed expansion would proceed in stages, designed

to minimise the risks associated with the delivery of major

infrastructure projects, and would progressively increase

production rates for refined metal and concentrate during

ongoing construction. These stages would overlap to some

degree, resulting in virtually constant on-site construction for

about 11 years. Off-site infrastructure would be timed to deliver

the necessary inputs to the expanded operation as necessary

(see Figure 5.7). A brief description of the indicative stages is

presented in Table 5.3. When dates are mentioned in the

context of the project activities it has been assumed that all

neccessary approvals would be obtained in 2010 and work

commenced soon afterwards. The project configuration is based

on an 11-year construction period, however, the project

schedule ultimately will depend on the timing and nature of

government approvals and the final investment decision of the

BHP Billiton Board.

Except where impacts are associated specifically with the initial

or intermediate development stages (for example, in the

assessment of road traffic, which will decrease following the

construction of the rail line), the impact assessment chapters

within the Draft EIS consider the impacts associated with the

project at full operating capacity.

The assessment within the EIS is based on operation at full

capacity (60 Mtpa for the expanded operation) until Year 40 at

which time the operation would be decommissioned and

rehabilitated. Infrastructure associated with the operation at

Year 40, and the potential strategies for decommissioning and

rehabilitation of the project components is described in

Chapter 23, Rehabilitation and Closure.

The following sections provide detailed explanations about how

each of the major infrastructure elements would be constructed

and operated. Appendix F2 provides concept design drawings

for many of these infrastructure components.

5.4 mining

5.4.1 overview

A new open pit mine would be developed to extract ore from

the southern part of the Olympic Dam ore body. The open pit

mine would involve drilling and blasting mine rock and ore, and

loading the blasted material by electric rope shovels, hydraulic

shovels and front end loaders into haul trucks which would haul

the ore to primary crushers and the mine rock to the RSF. The

open pit mine would commence as soon as possible after all

necessary approvals had been received and first ore would be

reached in about Year 5 or 6 (i.e. about 2016). From first ore it

would take approximately five to six years to reach full capacity

of mining (about 60 Mtpa of ore).

The major features of the open pit mine are detailed in

Table 5.4. As the volumes of ore and mine rock can vary from

year to year, the data are indicative. Figure 5.8 illustrates the

proposed location and size of the main expansion components

at Olympic Dam at Year 40.

The open pit mine development would increase the current

demand for energy, water, workforce and explosives. Indicative

major materials requirements for the proposed mining operation

are provided in Table 5.5.

table 5.3 indicative staging and timing for the key components of the proposed expansion

stage timing Description

Initial development (0–20 Mtpa ore)

Year 0 to Year 6 (a) Initial development of the pre-mine infrastructure and establishing the new open pit mine to deliver 20 Mtpa of ore to a new concentrator plant, specifically:

establish the open pit groundwater depressurisation infrastructure•provision of pre-mine infrastructure•extracting 390 Mtpa mine rock and 20 Mtpa of ore following pre-mine completion•construction of a new concentrator plant to produce concentrate for export•construction of a new hydrometallurgical plant to extract additional uranium•

(b) Development of off-site infrastructure associated with the initial mining development and concentrator plant (see Figure 5.7)

Intermediate development (20–40 Mtpa ore)

Year 6 to Year 9 (a) Expansion of the open pit mine, concentrator plant and hydrometallurgical plant to extract and process up to 40 Mtpa of ore

(b) Expansion of the existing smelter to allow smelting of up to 800,000 tpa of copper concentrate

(c) Development of new or expanded infrastructure to support the increased capacity of the expanded mining and metallurgical plants (see Figure 5.7)

Full capacity of expansion (40–60 Mtpa ore)

Year 7 to Year 11 (a) Expansion of the open pit mine, concentrator plant and hydrometallurgical plant to extract and process to achieve full operating capacity of up to 60 Mtpa of ore

(b) Expansion of the coastal desalination plant, construction of additional housing within Roxby Downs and decommissioning of some Hiltaba Village accommodation as dictated by demand

(c) Development of new or expanded infrastructure to support the increased capacity of the expanded mining and metallurgical plants (see Figure 5.7)

Olym

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ental Impact Statem

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5

PROJECT COMPONENT PREDICTED CONSTRUCTION PERIOD1

2010 2011 2012Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

Removal of overburden

Mining of first ore

Desalination plant

1 Based on government and BHP Billiton Board approval in 20102 ODX - Olympic Dam Expansion

Metallurgical plant

40 Mtpa

60 Mtpa

2013Q1 Q2 Q3 Q4

2014Q1 Q2 Q3 Q4

2015Q1 Q2 Q3 Q4

2016Q1 Q2 Q3 Q4

2017Q1 Q2 Q3 Q4

2018Q1 Q2 Q3 Q4

2019Q1 Q2 Q3 Q4

Pimba intermodal For materialstransport

Transmission line In time for increasedelectricity demand

Gas power plant/pipeline In time for increasedelectricity demand

Roxby Downs expansion

Hiltaba Village Initial development as soon as possible; further development to match demand

Initial development as soon as possible; further development to match demand

Airport Existing Airport Relocated for RSF growth

Darwin Port In time for exporting concentrate

Rail In time for importing sulphurand exporting concentrate

plus 135 ML/d for ODX2 In time for processing 40 Mtpa

plus 200 ML/d for ODX2 In time for processing 60 Mtpa

Landing facility In time for transportof pre-assemblies

Sulphur handling facility

Access corridor

In time for processing first ore

Water supply pipeline In time for processing first ore

20 Mtpa In time for processing first ore

Ongoingmining

Ongoingprocessing

In time forprocessing first ore

In time for transportof pre-assemblies

70 ML/d for ODX2 plus80 ML/d for government

Figure 5.7 Predicted timing of construction for major project components

Olym

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ental Impact Statem

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Figure 5.8 Location and size of major expansion components at Year 40

Overland ore conveyor

Major haul roads

Rail alignment




Open pit pushbacks

Year 5

Year 10

Year 20

Year 400 1 2 3 4 5

km

Landfillzone

ExistingBorefield Road

Open pit

Mine maintenance industrial area


Tailingsstorage facility

Primary crushers

Haulageaccess

corridors

Rail terminal

Metallurgicalplant

Laydownarea

On-site gas-firedpower station option

Intake electricalsubstation

Explosives storagefacility

Run-of-minestockpile

RelocatedBorefield Road

Low gradeore stockpile

On-site sewagetreatment

Figure 5.8 Location and size of major expansion components at Year 40


5

5.4.2 context

The most notable mineral and energy resources in South

Australia are at Olympic Dam (copper, uranium, gold and silver),

Leigh Creek (coal), Prominent Hill (copper and gold), Beverley

(uranium), Honeymoon (uranium), the Eucla Basin (mineral

sands), the Gawler Craton (iron ore) and the Cooper Basin

(oil and gas) (see Figure 5.9).

Copper is mined in all Australian states and around the world.

To illustrate the scale of the proposed expansion, Table 5.6 and

Figure 5.10 show the 2006 production rates at a selection of the

major Australian and overseas mines.

Half of the world’s uranium is currently mined in Canada and

Australia. Table 5.7 and Figure 5.11 show the 2007 production

rates from individual mines and highlight the significance of the

proposed Olympic Dam expansion.

Chapter 2, Existing Operation, of the Draft EIS details the

current Olympic Dam mineral resource and ore reserve estimates.

5.4.3 construction phase

For the purpose of the Draft EIS, the construction phase is

defined as the period required to clear the vegetation, remove

the topsoil and the overburden (i.e. to reach the ore), plus the

initial ore extraction activities required to commission the

materials handling systems and metallurgical facilities.

table 5.4 indicative features of the open pit mine development

features proposed expansion

Mining method Open pit

Number of years to reach first ore 5–6

Ore mining rate (Mtpa) 60

Total material movement (Mtpa) 410

Length of the open pit at Year 40 (km) 4.1

Width of the open pit at Year 40 (km) 3.5

Depth of the open pit at Year 40 (m) 1,000

Area of open pit at Year 40 (ha) 1,010

Number of rope shovels 14

Number of haul trucks1 160

Number of ancillary heavy vehicles2 150

1 Haul fleet numbers increase with increased haul distance over time.2 Includes graders, rollers, front end loaders, water carts, drill rigs, dozers, compactors, scrapers and fuel and lube vehicles.

table 5.5 indicative major demands for the proposed open pit mine development

expansion requirement proposed expansion

Water demand (average GL per annum/ML per day) 6/32

Electricity consumption (MWh per annum) 283,000

Diesel usage (ML per annum) 350

Peak construction/shutdown workforce 3,000

Ongoing operational workforce 2,500

Ammonium nitrate (tpa) 110,000

Total land disturbance – open pit and RSF (ha) 7,730

Examples of activities that would typically be undertaken

during this phase include establishing the mine infrastructure

and facilities, the mine materials handling systems (i.e. the

primary crushers and conveyors), the RSF, mine maintenance

facilities, surface and groundwater management systems

(including depressurisation wells), and sand stockpiles. Mine

rock and ore material would be drilled, blasted, loaded and

hauled during this phase. Monitoring would be undertaken to

confirm that air quality, noise and vibration levels and

equipment productivity parameters were within predictions.

Depressurisation

The area in the vicinity of the new open pit would be

depressurised before mining commenced to control potential

inflows of groundwater to the pit and to reduce residual pore

pressures behind the pit walls. This activity would be essential

to create drier and safer mining conditions. Depressurisation

would continue for the life of the open pit mine at a rate of

abstraction of about 5 ML/d, but dewatering would be at its

greatest (up to about 15 ML/d) up to Year 6. Water abstracted

from the open pit depressurisation would be used for dust

suppression and construction activities.


table 5.6 copper mine production figures (2006) compared with the current olympic Dam and proposed expansion

mine company mining method country copper mine production

capacity1 (ktpa cu)

Escondida BHP Billiton Group, Rio Tinto,

Japan Escondida

Open pit Chile 1,311

Codelco Norte Codelco Open pit Chile 957

Olympic Dam (expanded) BHP Billiton Open pit and

underground

Australia 750

Grasberg P.T. Freeport Indonesia, Rio

Tinto

Open pit and

underground

Indonesia 750

Collahuasi Anglo American, Xstrata plc,

Mitsui, Nippon

Open pit Chile 450

Morenci Freeport McMoran Copper &

Gold, Sumitomo

Open pit United States 430

Taimyr Peninsula Norilsk Nickel Open pit and

underground

Russian Federation 430

El Teniente Codelco Underground Chile 418

Antamina BHP Billiton Group, Teck,

Xstrata plc, Mitsubishi

Open pit Peru 400

Los Pelambres Antofagasta Holdings, Nippon

Mining, Mitsubishi Materials

Open pit Chile 335

Batu Hijau P.T Pukuafu Indah, Newmont,

Sumitomo Corp., Sumitomo

Metal Mining

Open pit Indonesia 300

Bingham Canyon Kennecott Open pit United States 280

Andina Codelco Open pit and

underground

Chile 236

Olympic Dam BHP Billiton Underground Australia 235

Zhezkazgan Complex Kazakhmys Open pit and

underground

Kazakhstan 230

Los Bronces Anglo American Open pit Chile 226

Rudna KGHM Polska Miedz S.A. Underground Poland 220

El Abra Codelco, Freeport McMoran

Copper & Gold

Open pit Chile 219

Mount Isa Xstrata plc Open pit and

underground

Australia 212

Toquepala Southern Copper Corp. Open pit Peru 210

Cananea Grupo Mexico Open pit Mexico 210

1 Sourced from International Copper Study Group 2007.


5

Coober Pedy

ProminentHill

Olympic Dam

Leigh CreekBeverley

Honeymoon

Cooper Basin

Eucla Basin

Gawler Craton

ADELAIDE

Lambina

FlindersIsland

SpencerGulf

GulfSt

Vincent

Operating mine

Prospect

Mining lease

Exploration lease

Proclaimed Precious Stones Field

Geothermal Exploration Licence



EIS Study Area

OLYMPIC DAM

Andamooka

Andamooka Proclaimed Precious

Stones Field

Inset

See inset

0 50 100 150 200 250km

Figure 5.9 Mining and energy resource development in South Australia

The proposed design for depressurisation would include some

or all of the following components:

The cover sequence is likely to be depressurised using about •

20–35 wells located in the Corraberra Sandstone and

Arcoona Quartzite (see Chapter 12, Groundwater).

Temporary wells would be located inside the area of the pit

void prior to pre-stripping to remove groundwater, and

permanent wells would be located around the perimeter of

the open pit to intercept groundwater that flows toward the

pit walls (see Figure 5.12). Some water would enter the pit

and this would be managed with in-pit horizontal drains,

in-pit wells and pumping from sumps in the pit floor.

The low permeability cover sequence and basement rocks •

would be depressurised using in-pit horizontal drain holes

and (potentially) by drain holes drilled from an underground

access tunnel.

Additional wells may be located away from the immediate •

pit edge, and away from the fractured basement rock to

intercept and manage areas of higher inflow.

Grading of the landscape and building of a pit perimeter •

bund would prevent significant stormwater run-off entering

the pit.

Sumps and a series of mobile and primary transfer pumping •

stations would manage rainfall that falls directly into the pit.

Water that accumulated in the pit during significant rainfall

events would either be pumped out and discharged into

natural depressions or used in the pit for dust suppression.


Source: International Copper Study Group 2007

0

200

400

600

800

1,000

1,200

1,400

Esco

nd

ida

Co

del

co N

ort

e

Oly

mp

ic D

am(e

xpan

ded

)

Gra

sber

g

Co

llah

uas

i

Mo

ren

ci

Taim

yr P

enin

sula

El T

enie

nte

An

tam

ina

Los

Pela

mb

res

Bat

u H

ijau

Bin

gh

am C

anyo

n

An

din

a

Oly

mp

ic D

am

Zhez

kazg

an C

om

ple

x

Los

Bro

nce

s

Ru

dn

a

El A

bra

Mo

un

t Is

a

Toq

uep

ala

Can

anea

Co

pp

er m

ine

cap

acit

y (k

tpa

Cu

)

Figure 5.10 World copper mining production in 2006

Figure 5.11 World uranium mining production in 2007 relative to the proposed expansion

0

2,000

Source: World Nuclear Association 2008

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

20,000

Oly

mp

ic D

amp

rop

ose

d e

xpan

sio

n

McA

rth

ur

Riv

er

Ran

ger

Oly

mp

ic D

amex

isti

ng

op

erat

ion

Rö

ssin

g

Kra

zno

kam

ensk

Rab

bit

Lak

e

Ako

uta

Arl

it

Akd

ala

Zafa

rab

ad

Bev

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y

McC

lean

Lak

e

Ura

niu

m p

rod

uct

ion

(t

of

U3O

8)


5

table 5.7 selected uranium mine production figures (2007) compared to the current olympic Dam and proposed expansion1

mine country company mining method estimated production capacity per annum

(tonnes of u3o8)

Olympic Dam – proposed expanded operation

Australia BHP Billiton Open pit and underground 19,000

McArthur River Canada Cameco Underground 7,199

Ranger Australia ERA (Rio Tinto 68%) Open pit 4,589

Olympic Dam – existing operation

Australia BHP Billiton Underground 4,5002

Kraznokamensk Russia TVEL Underground 3,037

Rössing Namibia Rio Tinto (69%) Open pit 2,583

Arlit Niger Areva/Onarem Open pit 1,750

Rabbit Lake Canada Cameco Underground 1,544

Akouta Niger Areva/Onarem Underground 1,403

Akdala Kazakhstan Uranium One In situ leach 1,000

Zafarabad Uzbekistan Navoi In situ leach 900

McClean Lake Canada Cogema Open pit 734

Beverley Australia Heathgate In situ leach 634

1 Sourced from World Nuclear Association 2008.2 Olympic Dam nameplate capacity, actual production in 2007/08 was 4,144 tonnes of uranium oxide.

The quality of groundwater pumped during depressurisation

activities would be very low (with total dissolved solids of

around 40,000 to 200,000 mg/L). It would be used primarily for

dust suppression, although some may be desalinated at the

on-site desalination plant for use within the metallurgical plant.

A monitoring program using piezometer monitoring wells would

be established to review the depressurisation system and

optimise its performance.

pre-mine infrastructure

Infrastructure would need to be established prior to the surface

mining operations commencing. This includes truck and shovel

assembly facilities, relocation of roads and services, a mine

maintenance industrial area (i.e. workshop), a power supply to

electric rope shovels and electric drills, refuelling and explosive

facilities and offices for mining contractors.

The mine maintenance industrial area would be located to the

west of the proposed open pit and comprise a suitably sized

enclosure for servicing ultra-class haul trucks, plus hardstand

areas, bunded areas for hydrocarbon storage and equipment

warehousing (see Figure 5.13).

The existing desalination plant would be decommissioned after

a new desalination plant had been commissioned (see

Figure 5.12 for locations). Infrastructure from the existing

desalination plant would be relocated and reused in the new

desalination plant to provide additional on-site desalination

capacity as appropriate.

The mining contractor pre-strip facility, assembly area for

mining (which includes offices), the laydown facility and the

civil crusher are shown on Figure 5.12. All but the laydown

facility would ultimately be covered by the expanding RSF.

The pre-strip facility would be the maintenance and operational

area for the pre-strip contractor. The pre-strip assembly area

would be used to assemble the mining haul trucks and shovels.

The civil crusher would be used to crush rock for use as

aggregate in construction of building pads, concrete

aggregates, roads and other construction activities.

The operation of the proposed open pit mine, combined with

existing usage in the underground mining operation, would

require a significant quantity of explosives. A dedicated

explosives facility would be constructed (see Figure 5.5 for

location) to produce and store the explosive products used in

the mine. This facility would consist of the following

infrastructure:

an ammonium nitrate storage area•

emulsion storage tanks•

gasser storage, manufacture and delivery facilities•

detonator magazine•

high explosives magazine•

diesel storage facility•

workshop and offices.•

The facility would be managed in accordance with relevant acts,

regulations and standards which dictate certain storage,

handling and use requirements, together with stringent security

and clearance requirements.

Olym

pic Dam


ental Impact Statem

ent 2009106

Mine maintenance industrial area

Open pit

Civil crusher

Pre-stripassembly area

Laydownfacility

New on-sitedesalination plant

Existing on-sitedesalination plant

Roxby Downs

OLYMPIC DAM

0 0.5 1 1.5 2 2.5km




EIS Study Area

Depressurisation well

Figure 5.12 Indicative location of open pit mine depressurisation wells and initial infrastructure

Olym

pic Dam


ental Impact Statem

ent 2009107

5Welding and abrasive

blasting area

Permanent contractors area

Ancillaryworkshop

Heavy vehiclewash-down area

Heavy equipmentworkshop and warehouse

Tyre changingworkshop

Administrationarea

Light vehiclemaintenance

0 0.1 0.2 0.3 0.4 0.5km

Mine maintenanceindustrial area

Conceptual layout

Proposed location

Figure 5.13 Indicative configuration of the proposed mine maintenance industrial area


pre-strip

The next step in constructing the open pit mine involves

progressively removing vegetation, sand dunes and topsoil

from the open pit footprint. These works, known as the

pre-strip phase, would excavate material using general earth

moving equipment.

During the pre-strip phase, a portion of the sand would be

stockpiled in designated locations for use in backfilling the

underground mine, smelter flux and as a material for use in

constructing the infrastructure. Where appropriate, topsoil

would be stockpiled for use in future rehabilitation activities.

pre-mine

At an estimated depth of 10–40 m below the surface, the

mobile equipment would be unable to dig the material in situ

and hard rock mining would commence. Hard rock mining

involves standard drilling, blasting, loading and haulage

activities and would commence in the first 12 months and

continue for the life-of-mine.

Pre-mine at BHP Billiton’s Spence mine in Chile

Open pit benches at BHP Billiton’s Escondida mine in Chile

It is envisaged that the mining equipment fleet would reach

near full operational capacity to deliver 20 Mtpa of ore in Year 6.

As the operation developed, the average haulage distance and

associated vertical lift of material would increase, and

additional haul trucks and associated equipment would be

added to maintain the anticipated rate of material movement.

The rock generated at depths of greater than approximately

40 m would be used to construct ramps for access to the RSF

tip-heads, for constructing the base layer of the RSF, and for the

initial TSF walls (see following section for details).

5.4.4 operation phase

The operation of the proposed open pit would use traditional

large-scale open pit metalliferous bulk mining techniques as

described in Figure 5.14 and illustrated in Figure 5.15. It is

envisaged that a combination of large electric rope shovels and

various sized diesel hydraulic shovels, excavators and front-end

loaders would be used to load overburden and ore into large

dump trucks. Typically, electric rope shovels would load

ultra-class trucks (i.e. trucks with a payload capacity of greater

than 300 t) while the hydraulic machines would load ultra-class

or smaller sized trucks based on the size of the loading unit and

the specific application.

During the operation phase, the open pit would be expanded

through a series of push-backs or circumferential strips that

would expose additional ore sequentially (see Figure 5.8). These

push-backs would be 150–400 m wide, and multiple push-backs

would be undertaken simultaneously to provide sufficient

working room to operate the required equipment and facilitate

the regular exposure of ore.

Each push-back would be developed by removing a series of

production benches. For operations using large electric rope

shovels, the height of the production benches would be in the

range of 14–20 m. Hydraulic excavators would typically operate

on benches 3–10 m high (see Figure 5.15).

As the mine pit deepens, a network of in-pit haulage roads and

ramps would be developed to allow the mine rock and ore to be

transferred to the surface. These haulage ramps would spiral

around the outer wall of the pit and vary in width between

40 and 100 m (i.e. wide enough to permit two-way traffic for

the mine haul trucks).

The bench face batter angle excavated by a rope shovel is

typically between 60 and 90 degrees, depending on the

structure of the rock mass encountered. Narrow benches

(or berms) would generally be developed at regular vertical

intervals to catch any loose material that rills down the pit wall.

These catch berms, together with the network of mine haulage

ramps and benches, would effectively reduce the overall pit

wall angle to a range of between 35 and 53 degrees, depending

on the specific local stability and structure of the rock mass

(see Figure 5.15).


5

Figure 5.14 Proposed mining method

MINING

Blasting

Haul road wateringand maintenance

Loading of haultrucks with ore

Ore haulage torun-of-mine (ROM)

stockpile

Mine rock haulageto rock storage

facility

ROM ore crushingand overlandconveying toore stockpile

Drilling

Loading of haultrucks with mine

rock

Watering ofhigh-traffic areas

SeeFigure 5.21

ORE PROCESSING


TYPICAL SECTION OF THE PIT WALL

Typicalnon-haul

road bench

3–10 mfor hydraulicexcavators

14–20 mfor electricrope shovels

Typical haul road40–100 m wide

depending on location

~ 20 m

Basement

Overall pit wall slopebetween 35 and 53°

Typicalbench wall

60–90°

TYPICAL OPEN PIT

Top of main rampout of open pit

Drilled out pattern aboutto be charged with explosives

Shovels loadinghaul trucks

Empty haul truckreturning to shovel

Loaded haul truck goingto run-of-mine stockpile

Drill rig drilling out anew pattern

Typical non-haulroad bench


Typicalbench wall

Catchberm

Catchberm

Typical haul road

Figure 5.15 Indicative cross-section of the proposed open pit


5

Drilling

Specially designed rigs drill large diameter vertical holes

into the initial bench level. Drill patterns are designed on a

case-by-case basis to yield the optimal fragmentation. Due to

the hardness variability of the rock to be mined, production

blast holes would be sized to optimise cost and fragmentation

results, with larger holes used in the overburden. Smaller

diameter holes may be used for controlled blasting adjacent to

pit walls and other specialist applications. Drilled holes would

then be charged with explosives.

charging and blasting

Blasting to achieve the desired fragmentation would use

industry standard ammonium nitrate-based bulk blasting

products and initiation systems. A new explosives facility would

be constructed to store the explosives prior to use. This would

be located to the north of the RSF (see Figure 5.8).

When complete, the drill holes would be charged (i.e. the holes

are loaded with detonators, boosters, high explosive products

and stemming). Stemming (i.e. the placing of aggregate

material or drill cuttings in the top of each blast hole) is

typically used to maximise blast efficiency by ensuring the

energy from blasting goes into the surrounding rock and not out

the top of the hole. This also reduces dust generation.

Once charging was complete, the down-hole detonators would

be linked together at the surface. Detonation of the blast would

occur at a pre-arranged time known as firing time. During these

times the surrounding area would be cleared of personnel and

equipment to a safe distance and the blast would be detonated

remotely using non-electronic and/or electronic initiation

techniques. The detonation of the charges would be sequenced

over a short period in order to maximise blast efficiency and

minimise the generation of dust, vibration and flyrock. Typically,

a number of blasts would be detonated separately within a

single firing time. The objective of the blasting process would

be to present well-fragmented rock that could be efficiently

excavated and removed from the pit.

Blast sizes would range from around 100 to 500 kt, with the

total material blasted ranging between 1.5 and 3 Mt. Blasting

would generally occur every second day.

Loading and hauling

Following blasting, the fragmented mine rock and ore would be

loaded into haul trucks by a rope shovel and removed from the

pit via a system of pit ramps. Ore would be tipped onto the

run-of-mine (ROM) ore stockpile or directly into the primary ore

crusher. Mine rock would be hauled to tip-heads at the RSF.

Haul roads would be constructed of materials excavated from

the pit, and would be watered regularly by water carts using

chemical suppressants to provide a compacted all-weather

surface with minimal potential for dusting.

This cycle of loading and hauling would be continuous, with an

empty truck arriving at the shovel just as the previous truck

completed loading. Typically, a rope shovel would require four

passes or buckets (dippers) to load an ultra-class haul truck,

and this would normally take two to three minutes. Hydraulic

excavators and front-end loaders would be used where digging

space was restricted, or in situations where more precision was

required during the excavations.

A bulldozer and water truck would operate in the general area

of loading operations to tidy up spilt rock in the loading zone,

level the loading zone and reduce dust.

Dumping

Dumping is the process of discharging rock from the tray of the

haul truck after it arrives at a tip-head, either on the ROM

stockpile or the RSF (see Section 5.4.6 for details of the

proposed RSF). Once at the stockpile or RSF the truck would

reverse to a tip-head and raise its tray to discharge the load.

The dumping cycle would take approximately 90 seconds per

load. Once the load was discharged, the tray would be lowered

and the truck would return to the shovel to be loaded again.

Typically, dumping would be arranged so that as one truck

finished dumping, it would be replaced by another loaded truck.

Given the size of the haul truck fleet, however, it is very likely

that multiple tipping would occur at each tip-head. A bulldozer

would operate at the ore stockpiles and RSF to maintain the

haul road surface and the windrow at the tip-head.

crushing

The ore would be crushed by gyratory pit-rim crushers (primary

crushers) to reduce the average particle size distribution to that

required to suit the metallurgical plant design. After crushing,

the ore is transferred to the metallurgical plant ore stockpile by

overland conveyor.

Truck loading in Chile


The dump pocket for the primary crushers would be designed so

that when operational conditions allow, the large haul trucks

would be able to deliver ore directly to the crusher. However,

when not available, the large haul trucks coming from the

bottom of the pit would place their loads on large ore stockpiles

(termed ROM stockpiles) immediately adjacent to the crusher

dump pocket. Front-end loaders would then take ore from these

stockpiles and load smaller trucks that would deliver the ore to

the crusher bowl. The ROM stockpile, primary crushers and

overland conveyor locations are shown in Figure 5.8.

5.4.5 chemicaL storage anD use

The quantities of each reagent required for the proposed mining

operation are listed in Table 5.8.

5.4.6 rock storage faciLity

This section provides a context to the proposed Olympic Dam

RSF by comparing it with similar facilities at other mines. It

also describes how the RSF would be designed to maximise

short- and long-term stability and manage the potential for

mineral leaching and acid generation.

overview

The open pit mine would also extract non-mineralised and

low-grade or non-economic rock (collectively termed ‘mine

rock’). Haul trucks would place this material in a dedicated RSF,

with the low-grade material (i.e. the material that was below

the current economic cut-off grade) being located in a separate

area or stockpile so that it could be recovered from the RSF

later if the value of the material increased.

During the pre-strip and pre-mine phases of the open pit mine

development, almost all material mined would be transported

to the RSF, except for those materials set aside for use as

construction materials. Up to 390 Mtpa of mine rock is expected

to be extracted when the open pit first intersects ore,

decreasing to about 350 Mtpa of mine rock when the ore

production rate stabilises at 60 Mtpa of ore. As the mine rock

consists of material of different geochemical and geotechnical

properties, the RSF would be designed to achieve particular

performance outcomes, which are outlined in the following

sections.

context

RSFs are used by all open pit mining operations to store the

non-economic material encountered while extracting the

economic ore from the pit. The mine rock production rates for

some of these facilities are presented in Table 5.9.

Design

The key design features of the proposed RSF at Olympic Dam

are listed in Table 5.10.

By Year 40, a total of approximately 12,700 Mt of mine rock

(non-mineralised) and low-grade material would have been

generated. Some of the mine rock material would be used in the

construction of other infrastructure for the expanded project

within the expanded SML (such as the construction of tailings

cell walls and haul roads), and some material would be

stockpiled for use during the operation phase of the project

(such as sand used for flux within the existing smelter). The

remaining mine rock would be managed in the RSF.

Starter pit at BHP Billiton’s Spence mine in Chile

table 5.8 indicative mining reagent usage per annum and storage methods

Description proposed expansion storage method

Ammonium nitrate (t) 110,000A dedicated explosives yard similar in design and operation to the existing site explosives yard, built to relevant specifications

Emulsion (t) 4,500

Pentaerythritol tetranitrate (PETN) (t) 129

Oil – hydraulic (L) 2,189,000

Stored in bunded compounds within the mine maintenance industrial area

Oil – engine (L) 2,085,000

Degreaser (L) 51,000

Brake fluid (L) 400

Detergent (L) 400,000

Diesel (ML) 350 Bunded above ground storage tanks complying with AS 1940

Dust suppression chemical (ML) 5 Bunded above ground storage tanks


5

Trucks building a rock storage facility in Chile

table 5.10 indicative features of proposed rsf


Estimated stored mass at Year 40 (Mt) 12,700

Bench height (m) 10–50

Maximum dump face height (m) 20–75

Maximum RSF slope angle (degrees) 37

Maximum overall RSF slope angle (degrees) 30

Method of construction Truck dumped

Proportion of reactive1 versus total mine rock (% by mass) 29

Selective placement of reactive mine rock Yes

Benign base layer to be constructed Yes

Estimated final footprint (ha) 6,720

Estimated final height (m) Approximately 150 m above ground level

1 Reactive material is defined later in this section.

table 5.9 selected indicative mine rock production figures compared to the proposed open pit operations

mine company country/australian state indicative mine rock production capacity, excluding ore (mtpa)

Olympic Dam – proposed expansion

BHP Billiton South Australia 350–390

Escondida BHP Billiton Group (57.5%)

Rio Tinto (30%)

Mitsubishi (12.5%)

Chile 2741

Grasberg Freeport-McMoRan C&G, Rio Tinto Indonesia 183.52

Bingham Canyon Kennecott Utah Copper North America 97.51

Fimiston Kalgoorlie Consolidated Gold Mines

Western Australia 69.53

Prominent Hill OZ Minerals South Australia 44.64

Cadia Hill Newcrest Mining Limited New South Wales 36.25

Telfer Newcrest Mining Limited Western Australia 29.45

1 Minera Escondida 2008; 2 Freeport-McMoRan Annual Report 2006; 3 Newmont Sustainability Report 2005; 4 Oxiana Limited Sustainability Report 2007; 5 Newcrest Mining Concise Annual Report 2006.


The key design principles that influenced the design of the RSF

were:

maintaining suitable buffer distances to key infrastructure •

and Arid Recovery

the stability of the RSF structure•

the size and location of the footprint•

the economic aspects of the RSF to minimise double •

handling and to optimise horizontal versus vertical haulage

distances

the geochemical and physical properties of the mine rock in •

order to minimise the potential for releasing metal-rich and

acidic leachate from the base of the structure

the potential to emit dust and radon.•

RSF layoutWhile the final RSF layout would be determined during detailed

design, the indicative location and size of the facility assessed

for the Draft EIS is shown on Figure 5.8.

The design principles for the RSF footprint aimed to achieve a

balance between the following:

creating a 500 m buffer between the RSF and the Arid •

Recovery area to the north of the operation

allowing an area for the construction of the expanded •

metallurgical plant and mine maintenance industrial area

providing a separate area for the stockpiling of low-grade ore•

minimising haulage costs•

creating access corridors to allow haul trucks to travel to the •

edges of the RSF

maximising the distance between the RSF and Roxby Downs •

township and the proposed Hiltaba Village in order to

minimise potential dust and noise impacts

minimising the footprint of the RSF while maximising •

constructability, safety, operability and long-term stability.

Geotechnical stabilityThe RSF would be constructed by haul truck end-dumping

to generate slopes with a natural angle of repose (about

37 degrees). A series of batters would be added throughout the

RSF construction, limiting the overall average RSF outerface

slope to a maximum of 30 degrees.

For the purpose of optimising the construction sequence, the

facility has been modelled with an average bench height of

25 to 50 m. Mine rock characteristics and construction method

may create operational constraints on dumping lift heights that

would be studied and defined prior to operations commencing.

The RSF would be constructed on a base layer of end-dumped

and levelled benign mine rock placed over the top of a sand

dune/clay pan foundation, except in locations where the sand

had been stripped for use in construction and/or smelter flux, in

which case a base layer would be constructed on the sub-soil.

This would provide a stable base upon which to develop the RSF

and aid in managing potential leachate by disrupting

preferential flow pathways within the base layer of the RSF

(see Figure 5.16 and Chapter 12, Groundwater, for details).

There is no specific geotechnical limit to the height of the RSF,

and the final height would be determined through an economic

assessment of the costs associated with hauling mine rock

material either vertically or horizontally. For the purposes of the

Draft EIS the final height of the RSF would be 150 m above

ground level. The separation distance between the lower edge

of the RSF and the outer edge of the open pit would be

determined after considering the geotechnical stability of the

pit and RSF, and the requirements for infrastructure (e.g. haul

roads) between the two.

Geochemical and physical propertiesA variety of rock types would be selectively placed within the

RSF, with their differing geochemical and physical properties

influencing the design and construction of the facility. The rock

types have been divided into four classes based on their

potential reactivity (i.e. a measure of the likelihood that a rock

type will react in the presence of water and/or oxygen and

generate a leachate containing metals or acid):

class A – low grade ore (potentially reactive)•

class B – basement (potentially reactive)•

class C – overburden rock (benign) •

class D – overburden rock (acid neutralising). •

More than 2.5 million geochemical assays were undertaken to

understand the mineralisation of the ore body and categorise

the Olympic Dam rock types into their respective classes.

Descriptions of the mine rock classes are provided in Table 5.11

and the results presented in Figure 5.17.

In addition to selective placement in the RSF, the class C mine

rock would also be used in other areas of the operation. For

example, the Tregolona Shale and Arcoona Quartzite Red are

suited to providing cover material for decommissioned tailings

cells, while the Arcoona Quartzite White and Arcoona Quartzite

Transition, and the Corraberra Sandstone, are blocky materials

suited to tailings embankment and other structural uses.

The mine rock would be selectively placed within the RSF so

that class A and B materials would be enclosed by class C or D

materials, thereby limiting the exposure of class A and B

materials to rainfall and oxygen, and minimising the potential

for the mobilisation of metals in leachate.


5

PROPOSED ROCK STORAGE FACILITY (at 40 years)

Haulageaccess

corridors

Low grade ore(Class A) stockpile

Indicative cross-section location

Class C or Dmaterial


Class B, C or Dmine rock

Class B, C or Dmine rock

CROSS-SECTION

Traffic compactedin-situ material

Traffic compactedin-situ material


Natural ground surface (foundation)

Sand dune Sand dune

Swale

10 m

25 m

25 m

Figure 5.16 Indicative cross-section of the rock storage facility

table 5.11 geochemical classifications of mine rock types arising from the open pit mine

class geological unit geochemistry

A Low-grade ore (ODBC)Material with moderate metals mobilisation potential and some acid neutralising capacity and some acid generating capacity. May become valuable enough to process in future

B Basement (ODBC)Material with low-to-moderate metals mobilisation potential and some acid neutralising capacity and some acid generating capacity

COverburden (Tregolona Shale, Arcoona Quartzite Red, Arcoona Quartzite White, Arcoona Quartzite Transition, Corraberra Sandstone)

Material with low metals mobilisation potential

D Overburden (Andamooka Limestone, dolomite, calcareous clays)Material for which the neutralising potential greatly exceeds metals mobilisation potential


The extraction of the various classes of material over time

indicates that there are sufficient class C and D materials to

enclose all class A and B materials, even assuming that all class

B material is reactive, with about 41% of the enclosure capacity

used (see Figure 5.18).

Layers compacted by traffic would be generated through the

natural construction and operation of the RSF, reducing

infiltration and further limiting the potential for metals to

mobilise from class A and B materials (see Figure 5.16).

The external batters of the final RSF would be constructed of

class C or D materials (see Figure 5.16) as these areas are

generally subject to higher rainfall infiltration because it is not

possible to establish a traffic-compacted layer above them.

Internal benches would also be constructed of class C and D

materials where operationally possible. Class A material (i.e.

low-grade ore) would generally be stored in a separate section

of the RSF (see Figure 5.8) and would not be covered by benign

material during operation as this material may prove economic

to process as some point in the future. Class A material that

remained after operations ceased would be covered with benign

material at mine closure.

construction phase

In the initial RSF construction phase, haul truck ramps and

tip-heads would be developed to enable end-dumping of mine

rock and the placement of a base layer of class C or D material

to form the foundation of the RSF. The benign base layer would

be extended progressively, as required, in front of the

advancing RSF benches.

A portion of the sand mined initially would be placed in

stockpiles outside of the immediate RSF footprint. As these

stockpiles were depleted they would be replenished with

material sourced from the active mining area and relocated as

required to meet the ongoing needs of the expanded and

existing operation. Some limestone excavated from the open pit

would also be stockpiled for use as aggregate for concrete or

structural fill.

operation phase

The RSF would be developed simultaneously at a number of

heights, expanding outwards over time to the maximum RSF

footprint as shown in Figure 5.16.

During operation, multiple simultaneous tip-heads would be

established, with trucks moving to the tip-heads via haulage

access corridors, which are valleys in the RSF that allow haul

trucks to maintain access to the outer tip-heads (see

Figure 5.16).

Each tip-head would consist of a number of tipping faces, with

a windrow of approximately two metres in height, designed to

provide a safety barrier to the reversing haul truck. A bulldozer,

grader and water cart would operate as required at each

tip-head to maintain it in good condition.

Based on the geological model and economic cut-off criteria,

each haul truck load would be categorised into one of the

classes of rock outlined earlier, and would be tracked to the

tip-head using the Fleet Management System, enabling the

material to be selectively placed.

5.4.7 integration with the existing operation

Ore would continue to be extracted from the existing

underground mine simultaneously with the development of

the open pit mine, and would continue to be delivered to the

existing metallurgical plant for processing. As the open pit

expanded, it would intersect some of the southern sections of

the existing underground mine, resulting in decreasing output

of ore from the underground operations over time. Underground

mining may occur until at least Year 40.

Ore from the proposed open pit mine would typically be

delivered to the new metallurgical plant (see Section 5.5).

However, provision would be made for the cross feeding of

the ore streams to provide operational flexibility.

Class A

Class B

Class C

Class D

Class

A

B

C

D

Volume (%)

2

30

55

13

Weight (Mt)

242

3,483

6,275

1,494

Mine rock classification

Low grade ore

Basement mine rock

Benignoverburden material

Acid neutralisingoverburden material

Figure 5.17 Classification of mine rock to be stored in therock storage facility to Year 40


5Min

e ro

ck (

mill

ion

to

nn

es)

-

50

100

150

200

250

300

350

400

1 5 10 15 20 25 30 35

Production year

40

Min

e ro

ck (

mill

ion

to

nn

es)

-1 5 10 15 20 25 30 35

Production year

40

1,000

2,000

3,000

4,000

5,000

6,000

7,000

Class A: low grade ore

Class B: basement material

Class C: overburden (shales, quartzites and sandstones)

Class D: overburden (limestone, dolomite and clays)

Class A: low grade ore

Class B: basement material

Class C: overburden (shales, quartzites and sandstones)

Class D: overburden (limestone, dolomite and clays)

Figure 5.18 Mine rock extraction by class over time


There are several potential uses for the mine rock generated

during the open pit mining operation within the existing

underground mining operation:

limestone could be used to generate cemented aggregate •

fill (CAF) for backfilling primary stopes in underground

workings, and the existing limestone quarry would be

decommissioned

sand could be used as smelter flux•

cover sequence material (class C and D) could be used for •

the progressive decommissioning and rehabilitation of the

existing TSF cells

cover sequence material could be used to construct the •

embankments of TSF cells.

These uses would be investigated in greater detail during the

definition phase of the project, with the aim of minimising

disturbance and maximising beneficial reuse while ensuring

adequate material was available throughout the life-of-mine to

enclose the class A and B materials within the RSF.

5.5 processing

5.5.1 overview

A new metallurgical plant would be constructed to process the

ore mined in the open pit mine. The plant would consist of a

new concentrator and a new hydrometallurgical plant to extract

uranium from the tailings generated in the new concentrator.

The new metallurgical plant would be constructed over a

number of stages, each of about 20 Mtpa ore throughput and

designed to coincide with the ramp-up in the rate of mining in

the open pit. Ultimately, the new metallurgical plant would

process about 60 Mtpa of ore.

This plant would supplement the existing metallurgical plant,

which would continue processing ore from the either the

underground operation, or the open pit mine, at a rate of

around 12 Mtpa. Some connections between the existing and

the new metallurgical plant would be established in order to

maximise the combined production from both metallurgical

plants. The existing metallurgical plant would also be enhanced

by an expansion of the existing electrorefinery and the

optimisation of the existing smelter.

Tailings from both the existing and new metallurgical plants

would be combined in a new tailings disposal facility and then

pumped to a new TSF. The new TSF cells would be a refinement

of the existing TSF cell design, taking into account the 20 years

of operating experience with the existing cells and the

additional construction materials that will be available as a

result of the open pit mine.

Table 5.12 provides an indicative summary of the major features

associated with the expansion of the existing metallurgical

plant and the new metallurgical plant and Figure 5.19 illustrates

the location and footprint of the major metallurgical

components. A conceptual layout of the proposed new

metallurgical plant is shown as Figure 5.20.

The new metallurgical plant, combined with the optimisation of

the existing metallurgical plant, would increase the demand for

energy, water and sulphur. Indicative requirements for major

materials to support the proposed mining operation are shown

in Table 5.13.

5.5.2 context

The new metallurgical plant would include the construction of

the following facilities:

a new concentrator plant, including nine new grinding mills •

and new flotation circuits. The grinding mills would be

slightly larger than the current mills, and the flotation circuit

would be significantly larger, although it would operate in a

manner similar to the existing flotation circuit. The new

concentrator plant would also incorporate a more efficient

thickening stage, which would follow the flotation stage.

This would be designed to reduce the use of fresh water and

enhance the recycling of acidic liquor from the TSF

a concentrate filter plant to produce concentrate for export •

and load-out facilities to transfer the concentrate to the

rail terminal

table 5.12 indicative features of the expanded metallurgical facilities


Ore grinding rate (Mtpa) 60

Copper concentrate (ktpa) 1,8001

Refined copper (ktpa) 5152

Uranium oxide (tpa) 14,5002

Gold bullion (oz/a) 700,0002

Silver bullion (oz/a) 2,100,0002

Number of new grinding mills 9

Number of new acid plants 4 + 13

Number of new TSF cells 8 + 14

1 Of the 1,800 ktpa of copper concentrate produced, 1,600 ktpa would be prepared for export to off-site smelting facilities, and 200 ktpa would be directed to the expanded on-site smelter.2 Production numbers include copper, gold and silver production derived from off-site facilities processing Olympic Dam-generated copper concentrates, and represent production equivalents given typical metal recoveries at Olympic Dam.3 Four acid plants would be constructed in the new metallurgical plant, and one associated with the expansion of the existing smelter.4 An additional TSF cell has been allocated for construction as contingency against changes in the site water balance over time.

Olym

pic Dam


ental Impact Statem

ent 2009119

5

Overland ore conveyor

Electricalsubstation

Uranium solventextraction

Process waterponds

Sulphur handlingfacility

Countercurrentdecantation tanks

Tailsleach

Rail terminal

Flotation area

Grinding mills

Sulphur burning acid plants

Cogeneration plant

Tailings disposal

Uranium precipitationand packing

0 0.5 1km

Newacid plant

Feed preparationexpansion

Additionalanode furnaces

Acid line to newhydromet facility

New slagcooling

area

Electrorefineryexpansion

Existing smelter

Proposed smelter expansion0 0.1 0.2 0.3 0.4 0.5

km

Proposedmetallurgical

plant

Existingmetallurgicalplant

Hydrometallurgical plant

Concentrator

Figure 5.19 Indicative configuration of major metallurgical plant at Year 40

Olym

pic Dam


ental Impact Statem

ent 2009120

Sulphurhandling facility

Existingmetallurgical plant

Sulphur burningacid plants and

cogeneration plant Concentrator

Existingtailings storage facility

Figure 5.20 Conceptual layout of the proposed metallurgical plant at Year 40


5a new hydrometallurgical plant, including new tails leach •

tanks, new countercurrent decantation tanks and new

clarifier tanks. These would be larger than the existing

hydrometallurgical plant, but would operate in a similar

manner

a new uranium solvent extraction plant, including new •

raffinate ponds, new pulse columns and a new uranium

precipitation and calcination circuit. These would generally

be enlarged versions of the present solvent extraction

operation

a new tailings disposal plant that would handle both •

existing and new metallurgical plant tailings. This would be

larger than the existing facility and would be designed to

transfer tailings to the TSF at 52–55% solids, compared to

the existing facility which operates at around 47% solids

eight to nine new TSF cells. These would be a refined version •

of the existing TSF cell 4 design incorporating a new

centreline raise design instead of the current upstream raise

design. This change is possible because the more competent

mine rock extracted from the open pit would be used instead

of consolidated tailings for TSF wall construction. The

existing TSF seepage controls would be improved, using the

experience gained in operating the current TSF cells over

more than 20 years

four additional balance ponds to assist in the management •

of liquor decanted from the TSF

four additional acid plants, which would be similar, but •

larger, than the existing acid plant, and would be designed

to burn elemental sulphur to generate sulphur dioxide for

conversion to sulphuric acid, rather than using off-gas from

a furnace as occurs in the existing acid plant

an electricity cogeneration plant, in which steam-driven •

electrical turbines and generators use the heat produced

from burning sulphur in the new sulphur burning acid plant.

Currently, heat from sulphur burning within the existing acid

plant is directed to a heat exchanger and lost.

The existing metallurgical plant would be expanded and

optimised to provide synergies with the new metallurgical plant

and open pit mine. The significant aspects of the proposed

expansion of the existing metallurgical plant are:

modifications to optimise the existing smelter and •

associated infrastructure. This includes upgrades to the

existing concentrate leach, feed preparation and concentrate

feed system, modifications to the flash, electric and anode

furnaces, upgrades to the gas cleaning systems (if

necessary), and upgrades to the metal casting facilities

construction of a second acid plant adjacent to the existing •

acid plant, which would be similar in design and operation

to the existing acid plant

optimisation of the existing copper solvent extraction circuit •

and the existing electrowinning plant

expansion of the electrorefining tank house•

expansion of the existing precious metals recovery plant•

construction of additional infrastructure necessary to run •

the existing or proposed operation, including:

pipelines to transfer copper concentrate from the new −

metallurgical plant to the expanded concentrate leach

area of the existing metallurgical plant prior to feeding

into the existing smelter

pipelines to transfer tailings from the existing −

metallurgical plant to the new tailings disposal plant.

5.5.3 construction phase

Construction of the new metallurgical plant, and modification

of the existing metallurgical plant, would occur as necessary in

time to process the first 20 Mtpa of ore from the open pit.

Initially, three TSF cells and two balance ponds (see Section

5.5.6) would be required.

The intermediate development would expand the new

metallurgical plant to process about 40 Mtpa of ore through the

new concentrator and hydrometallurgical plant. Additional

grinding mills, flotation cells and an additional tails leach circuit

would be added. The existing smelter and associated

infrastructure would be modified to increase its capacity to

around 800,000 tpa. Two additional TSF cells and two balance

ponds would also be constructed during this time.

table 5.13 indicative major demands for the proposed new metallurgical plant


Water demand (average GL per annum/ML per day) 63.51/175

Electricity consumption (MWh per annum) 3,310,000

Sulphur (tpa) 1,720,000

Peak construction workforce 3,000

Ongoing operational workforce 1,000

Total land disturbance (including TSF) (ha) 4,690

1 Water demand for the new metallurgical plant would be met through a combination of process water generated at the desalination plant (about 75%) and liquor recovered from the TSF cells (about 25%) – see Section 5.7 for further information.


The final development would increase ore throughput to the full

operating capacity of around 60 Mtpa through additional grinding

mills, flotation cells and an expansion to the hydrometallurgical

plant. Two to three additional TSF cells would be constructed but

no additional balance ponds would be required.

Additional electricity, water infrastructure and workforce would

also be required during development to 60 Mtpa, and these are

detailed in their respective sections in this chapter.

Construction of the plantAccess and deliveries to the construction area would be via

road and/or the proposed new rail line. Materials would be

imported through Outer Harbor and the landing facility and

transported to pre-assembly yards at Port Augusta and

Olympic Dam.

Construction would begin with ground preparation for

foundations. Vegetation on the site would be cleared and

topsoil would be removed and stockpiled for reuse in

rehabilitation or landscaping. Graders, front end loaders and

bulldozers would level the ground to the required gradient. The

selection of appropriate foundations for the metallurgical plant

is not usually made until the detailed design stage, but,

normally, massive concrete foundations would be installed over

a compacted rock base. The fabrication and erection of the

buildings would follow, including erection of the mechanical,

piping, electrical and instrumentation components of the plant.

Containment bunding would be constructed around all material

storage areas in accordance with legislative requirements.

Testing and commissioningOnce the various process components have been constructed

and made ready for energising, the functional testing of each

component, system and separable portion would commence. To

minimise the risks associated with plant and equipment failure,

this pre-commissioning is typically executed using air or water,

rather than with process materials such as ore and chemicals.

Once pre-commissioning has been concluded, the various

processing areas would be mechanically complete and ready for

process commissioning with ore. The plant, equipment and

systems would then be tested for performance while operating

with ore, reagents and other process materials. When the

pre-determined level of output and quality is achieved, the

areas would be handed over to operations personnel for

optimisation and routine operation.

5.5.4 operation phase

The proposed new metallurgical plant, together with the

modified existing metallurgical plant, would operate as shown

in Figure 5.21 and as described in the previous sections. The

following sections describe the operation phase for each of the

metallurgical areas in greater detail.

concentrator plant

The new concentrator plant would grind ore from the open pit

mine to a size that permits the liberation of the copper-bearing

mineral from the remainder of the ore in the flotation section of

the concentrator. In addition, infrastructure for the handling

of off-site concentrates may be established to permit the

metallurgical processing of concentrate produced from other

operations. This would be added to the flotation feed tank

prior to the flotation circuit. The output of the concentrator

would consist of two streams: a copper-rich slurry, and a

uranium-rich slurry.

The following sections describe the concentrator process in

more detail, and a conceptual layout is presented in Figure 5.20.

Ore storage and handlingTwo overland conveyors would feed grinding mill feed

stockpiles of around 120,000 t total capacity, obtaining ore

from the open pit primary crushers (described previously). The

ore would be distributed to the stockpiles according to certain

ore characteristics (e.g. the copper-to-sulphur ratio) either by

two or three travelling and luffing stackers or by tripper

conveyors. Feeders underneath the stockpiles would direct ore

onto conveyors to the mills.

GrindingThe ore from the stockpiles would be mixed with process water

to form a slurry which would then be milled to the appropriate

product size to allow the copper-bearing minerals to be

separated from the remaining minerals during flotation. Nine

grinding mills would be necessary to grind the 60 Mtpa of ore.

These would be installed in stages, with three grinding mills

installed initially, and the subsequent installation of a further

three grinding mills in each of the intermediate and

development to full operating capacity phases. After grinding

the slurry would be stored in an agitated tank before being

directed to the flotation circuit.

FlotationA conventional flotation process similar to that presently used

at Olympic Dam would separate the copper-bearing minerals

from the other minerals in the ore (including uranium). Dosing

the flotation cells with chemical reagents enables the copper-

bearing minerals to float to the surface when air is blown

through the cells. The copper-bearing minerals are then

skimmed off to form a copper-rich slurry which would be

thickened and transferred to new concentrate storage tanks.

The remaining materials in the ore, including the unrecovered

uranium-bearing minerals, sink to the bottom of the flotation

cells where they are collected and sent for tailings thickening.

Tailings thickeningThe concentrator tailings thickening design is proposed to

reduce the amount of fresh water demand using recycled acidic

liquor collected from the TSF. This stage would consist of about

12 deep-cone thickeners for the flotation tailings stream,

thickening the slurry to about 65–70% solids. The thickened

slurry would subsequently be mixed with recycled acidic liquor

from the TSF before further treatment in the hydrometallurgical

section of the facility.


5

Figure 5.21 Proposed metallurgical processes (ore processing)

Newflotation circuit

Copperconcentrate

handling facility

Copperconcentratecontaining

uranium

New tailings disposalplant and tailings storage

(also receives tailingsfrom existing

hydrometallurgical plant)

Newgrinding mills

Ore stockpile(from open pit andunderground mine)

Existingconcentrator

Flotation tails

Flotationtails

Sulphuricacid

Taili

ng

s

Copperanodes

Refineryslimes

Flotationconcentrate

Flotationconcentrate

Flo

tati

on

con

cen

trat

e

New tailsleach circuit

New sulphurburning acid

plants

Expandedsmelter

Existinghydrometallurgical

plant

Newcounter currentdecantation and

clarification circuit

Expandedelectrorefining

facility

Existingelectrowinning

facility

New uranium solventextraction, precipitation,calcination and packing

Expandedprecious metalsrecovery plant

Gold and silverbullion

Coppercathode

Uraniumoxide

CONCENTRATOR SMELTER ANDACID PLANT

HYDROMETALLURGICALPLANTREFINERY


Concentrate handlingDuring the initial development copper-rich concentrate derived

from the new flotation circuit would be thickened and directed

to a new concentrate filter plant. Here it would be filtered

through six to ten filter presses to form a copper concentrate

solid containing about 10% moisture. This would be stockpiled

inside an enclosed shed (which can store around 100,000 t),

before it is loaded onto a train for export via the Port of Darwin

(see Section 5.9 for details). Ultimately, about 1.6 Mtpa of

concentrate would be exported.

Following an upgrade of the existing smelter (to increase its

capacity from 600,000 tpa of concentrate to 800,000 tpa), the

additional 200,000 tpa of copper concentrate would be directed

to the expanded concentrate leach plant from the flotation

concentrate storage tanks. Extra leach tanks would be added to

process the greater throughput.

hydrometallurgical plant

The hydrometallurgical plant recovers the uranium from the

flotation tailings generated within the concentrator plant.

A new hydrometallurgical plant would be built essentially

duplicating the existing hydrometallurgical process but without

the components to extract the copper.

The following sections describe the hydrometallurgical process

in more detail.

Tails leachTails leach is the process used to recover uranium from the

uranium-rich flotation tailings using sulphuric acid and oxidising

agents. The new hydrometallurgical plant would install up to

three trains of tails leach tanks with each train consisting of

8–10 covered and lined tanks. These would operate in a similar

manner to the existing tails leach circuit, however each train

would be able to leach around

20 Mtpa of flotation tailings, ramping up to match ore

production from the open pit mine. The leached material would

be discharged as a slurry and passed to the countercurrent

decantation circuit (see following section).

A bypass system comprising pumps and pipelines would be

installed to bypass the tails leach process should the tails leach

plant be unavailable. This would allow copper concentrate to be

generated for the smelter and export while maintenance to the

tails leach plant was undertaken. When the tails leach bypass

system was operating flotation tailings would be disposed of at

the TSF.

Countercurrent decantationThe countercurrent decantation (CCD) circuit allows uranium-

bearing liquor to be recovered and separated from the leach

residue. Slurry from the new tails leach circuit would be pumped

to the CCD circuit which would have three trains consisting of

six thickeners operating in series, each of around 20 Mtpa

throughput capacity. Flocculant would be mixed with the feed

material in each thickener to enhance the settling

characteristics of the solids.

The thickened residue from the last tank in the new CCD circuit

would be pumped to the tailings disposal area before being

discharged to the TSF. Uranium raffinate liquor (the low-

uranium bearing solution) from the new uranium solvent

extraction circuit would be added to this final thickener as a

wash solution with thickener overflow advancing in a

countercurrent manner to the solids. The overflow solution from

the first CCD thickener in each train would be pumped to the

pregnant liquor solution clarification circuit where entrained

solids would be removed.

Pregnant liquor solution clarificationClarification units, consisting of large tanks operating in a

manner similar to thickeners, would be used to remove

entrained solids from the pregnant liquor solution. Flocculant

and coagulant would be added to aid the clarification process.

The solids separated out during this process would be returned

to the CCD circuit and the clarified liquor solution would be

pumped to the pregnant liquor solution ponds. Additionally, a

series of PLS filters would be installed to remove any remaining

solid material.

These ponds would provide a buffer capacity between the tails

leach/CCD/clarification sections and the solvent extraction

circuit, enabling more consistent operation. Up to four pregnant

liquor solution ponds would be constructed to allow maximum

operational flexibility and each pond would be lined and have

an appropriate leak-detection system.

Uranium solvent extractionA new uranium solvent extraction (USX) plant would be

constructed. This plant would be similar in design and operation

to the existing USX plant, differing only in scale. It would have

three trains to cater for the ramp-up in the rate of mining over

time, each of which would be capable of operating

independently of the others. The two outputs from the new USX

plant would be uranium raffinate liquor (containing little

uranium) which would be directed back to the new CCD circuit,

and uranium-rich liquor which would be directed to the new

uranium precipitation circuit.

Uranium precipitation, calcination and packagingThe uranium precipitation circuit would remove uranium from

the uranium-rich stream produced by the new USX plant and be

similar in design and operation to the existing uranium

processing and handling infrastructure. Ammonia, stored in a

dedicated storage facility about 1 km to the west of the

proposed new metallurgical plant, would be used to produce a

uranium precipitate, ammonium diuranate (ADU) [(NH4)2U2O7],

commonly called yellowcake. The precipitate would be washed

and thickened and then pumped to the calcination area. Once

the uranium had been removed the remaining barren strip

solution would be recycled to the new uranium solvent

extraction circuit.

The new calcination plant would use two calcining furnaces to

oxidise the ADU and create uranium oxide (U3O8), which would

then be packed into 200-litre drums that would be automatically


5

filled and weighed in a sealed enclosure prior to transport

off-site as per the existing process.

Tailings thickening and disposalTailings from the existing operation would be pumped from the

tailings disposal area of the existing metallurgical plant to a

new common tailings disposal area to be combined with tailings

from the new hydrometallurgical plant. The combined slurry

would have a solids concentration of about 52–55%. The slurry

would be pumped and deposited to the new TSF cells (see

Section 5.5.6).

smelter

The existing smelter converts copper concentrate produced in

the concentrator plant, containing around 40% copper, to cast

copper anodes of about 99% copper. Slag, containing largely

iron and silica with small amounts of residual copper, is also

produced in the smelter. In order to meet the needs of the

expanded operation, the throughput of the existing on-site

smelter would be increased to receive about 800,000 tpa of

copper concentrate.

This would be achieved by expanding the existing smelting

infrastructure, the most significant of which would be the

installation of additional anode furnaces in the smelter, and an

additional acid plant for the treatment of the sulphur dioxide-

rich off-gas from the flash smelting furnace. The details of the

modifications necessary within the existing smelter are

provided in the following sections.

Concentrate leachThe concentrate leach circuit uses sulphuric acid to remove

uranium from the copper concentrate prior to smelting. The

discharged concentrate leach slurry would be thickened and

the solids would be filtered, washed and re-pulped with process

water and a caustic solution to neutralise the residual acid.

The leach liquor would be directed to the existing

hydrometallurgical plant for the recovery of uranium. The

filtered solids would be pumped to the existing feed

preparation plant for further filtration, stockpile blending and

drying, before being conveyed to an enclosed concentrate-

blending stockpile for smelting. One or two additional filter

presses and an extra steam dryer would be added to the

existing feed preparation plant to increase its capacity.

Feed preparationThe operation of the feed preparation plant has been described

above. The existing feed preparation plant would require an

additional steam dryer to meet the throughput requirements,

plus some minor infrastructure, such as additional conveyors.

Flash smelting furnaceThe dried copper concentrate from the feed preparation plant

reacts with oxygen and silica in the flash smelting furnace to

separate metallic copper from other minerals within the

concentrate.

Additional blister copper tapholes would be installed on the

eastern end of the existing flash furnace to meet the additional

throughput of copper concentrate. These tapholes would

discharge to a modified launder system so that the flash furnace

copper could be directed to the new anode furnaces. An

upgrade of the flash smelting furnace feed system would also

be required to ensure the furnace received sufficient copper

concentrate feed with the correct proportions of oxygen and

silica.

Additional ventilation would be installed in the smelter to

manage the gases generated through tapping the new blister

tapholes on the eastern end of the furnace. This system would

be similar to the existing taphole hood ventilation installed on

the existing tapholes, and would collect fugitive gases and

direct them to a dedicated stack to be located to the north-east

of the existing smelter building. The stack height would be

determined during detailed design (a height of 35 m has been

used for the purpose of the Draft EIS assessments), but it would

be sufficiently tall to ensure ground level concentrations of

emitted substances were acceptable and to avoid the potential

for ventilation gases to re-enter the smelter building.

Electric slag reduction furnaceThe existing electric slag reduction furnace treats the slag from

the flash smelting furnace, removing residual copper and

directing it to the anode furnaces. Modifications may be

required to the slag handling area of the electric slag reduction

furnace to meet the increased slag generation rates. This may

include additional slag tapholes and replacement of the existing

40 t slag tapping pots with 100 t slag pots. An upgrade to the

electric slag reduction furnace off-gas handling system may also

be required. This would include the installation of a larger

off-gas fan and minor modifications to associated infrastructure.

Uranium packing


Anode productionBlister copper produced by the flash smelting furnace and the

electric slag reduction furnace would be delivered to both

the existing anode furnaces and new anode furnaces, which

would be constructed on the north-eastern side of the existing

smelter building. Anode furnaces are used to further refine

the molten copper, which is cast into moulds in preparation for

final refining in the electrorefinery. The new anode furnaces

would be the same as those currently installed and would

feed a casting wheel, similar in design and operation to that

already used.

Off-gas from the new anode furnaces would be treated in a

new off-gas handling system. This would be a quench-venturi

style scrubbing system similar to those currently installed for

the existing anode furnaces. The scrubbed off-gas would be

directed to the main smelter stack most of the time, or to one

of the two acid plants during oxidation cycles.

Waste-heat-boilerThe existing waste-heat boiler would be modified with

additional steam tubes to increase its capacity to cool the

off-gas and generate steam for use in other sections of the

existing metallurgical plant.

Oxygen plantsAn additional oxygen plant would be constructed to supply

extra oxygen for use in the furnaces within the smelter. The

additional plant would be similar in design and operation to

the four plants already used in the existing operation.

AncillariesA number of other, smaller, components would need to be

upgraded to meet the demands of the expanded smelter. These

include additional compressed air capacity, additional storage

and handling capacity for reagents, additional infrastructure to

manage anodes (i.e. laydown areas and anode hauling

capacity), and expanded slag cooling areas.

acid plants

New acid plants would need to be constructed and operated

in order to meet the sulphuric acid needs of the on-site

consumers in the metallurgical plant, and to treat the high-

sulphur dioxide off-gas from the expanded smelter.

Construction of this infrastructure would be timed to coincide

with the expansion of the smelter and the construction of the

new hydrometallurgical plant.

Metallurgical gas acid plantOne additional acid plant would be constructed adjacent to

the existing acid plant to treat additional off-gas generated by

the modified smelter. This acid plant would be similar in scale

to the existing acid plant, with a capacity to generate around

1,500 t of sulphuric acid per day, compared to the existing

1,800 tpd acid plant. This new acid plant would be similar in

design and operation to the existing acid plant.

Sulphur dioxide-rich off-gas from the flash smelting furnace and

the anode furnaces (when in oxidation) would be treated

through the existing waste-heat boiler and electrostatic

precipitator to reduce the temperature of the gas and remove

most of the particulate matter. Following treatment in the

existing electrostatic precipitator, the off-gas stream would be

split between the existing acid plant and the new acid plant.

The off-gas in both acid plants would be cleaned (i.e. the

fluorides, chlorides and any residual particulate matter would

be removed) before entering the gas converter, where the

sulphur dioxide is converted to sulphur trioxide. This process

uses a vanadium-based or caesium-based catalyst. The sulphur

trioxide gas is then brought into contact with sulphuric acid,

which absorbs the sulphur trioxide and generates more

sulphuric acid. Unconverted sulphur dioxide and sulphur

trioxide are recycled around the acid plant in order to reduce

emissions to the atmosphere. This type of acid plant, termed a

double contact, double absorption acid plant, would typically

capture around 99% of the sulphur.

As with the existing plant, some elemental sulphur would be

burned in the new acid plant to increase the volume of sulphuric

acid produced and to maintain gas converter temperatures

during maintenance to the flash smelting furnace or associated

infrastructure.

Sulphur burning acid plantsFour additional acid plants would be constructed within the

new metallurgical plant to provide sulphuric acid. These acid

plants would be similar to the new smelter acid plant previously

described but would be larger. Each would have a capacity of

about 3,500 tpd of sulphuric acid, but this would only be

generated from burning elemental sulphur (i.e. these acid

plants would not treat off-gas from the smelter).

Waste heat generated from these new sulphur burning acid

plants would be recovered as steam by waste-heat boilers.

The steam would be directed to the cogeneration plant (see

Section 5.8.6 for a description of the proposed cogeneration

plant) to produce electricity, partially off-setting the scheduled

demand for electricity.

Elemental sulphur is necessary to ensure sufficient sulphuric

acid can be made to supply the hydrometallurgical plant. About

1.7 Mtpa of sulphur would be delivered by rail and conveyed

to a storage facility with a capacity of around 300,000 t (see

Figure 5.20). This facility would be enclosed within concrete

barriers and wind-disruptive fencing, similar to the existing

sulphur storage area.

refinery

The refinery area of the proposed plant is broadly divided into

three processes: electrorefining, electrowinning and precious

metals recovery. A new electrorefinery tank house would be

constructed within the existing metallurgical plant. The existing

electrowinning operations would require minor optimisation.


5

ElectrorefiningThe existing electrorefinery would be expanded through the

addition of an extra tank house located near the existing

metallurgical plant. The additional tank house would operate in

the same manner as the existing refinery, containing a number

of cells into which cast copper anodes were inserted. An

electrical current would be applied, plating the copper onto

stainless steel mother plates, and dropping the impurities,

including gold and silver, to the bottom of the cells. These

plates would then be removed from the cells, and the copper

stripped and bundled for sale to customers. The new

electrorefinery tank house would be fitted with new equipment

to prepare the anodes, strip the cathodes and bundle the copper.

ElectrowinningThe electrowinning operations would require only minor

optimisation to cater for the additional copper electrolyte

throughput from the existing copper solvent extraction plant,

such as refining the plating cycle times and optimising crane use.

Precious metals recoveryThe precious metals recovery plant takes the gold and silver

slimes collected from the bottom of the electrorefinery cells and

processes them (by removing impurities such as lead and

selenium) to form gold and silver bullion.

The existing precious metals recovery plant would be retained

and with minor metallurgical optimisation, the capacity would

be sufficient to handle the additional slimes throughput.

5.5.5 chemicaL storage anD use

No changes are proposed to the types of reagents used

throughout the metallurgical operation given the similarities

between the existing and new metallurgical plants. The volumes

of reagents used, however, would increase. Table 5.14 identifies

the indicative volumes of reagents and methods of storage that

would be required for the expanded operation. This table does

not include reagents generated on-site

(e.g. sulphuric acid, oxygen and nitrogen).

table 5.14 indicative annual metallurgical plant reagent requirements and storage methods

Description proposed expansion storage method

Ammonia (t) 11,000 Above ground bullet tanks

Boiler and cooler feedwater chemicals (t)

320 Self-bunded bulk containers

Caustic soda (t) 25,000 Dedicated, bunded reagents yard as per existing practice

Coagulant (m3) 31,700 Bunded tank

Coke (t) 18,300 Covered storage shed

Copper extractant (Oxime) (t) 880 Stored in bulk containers within a dedicated bunded area

Diesel (m3)1 16,000 Bunded tank conforming to the requirements of AS 1940

Diluent (m3) 14,500 Bunded tank conforming to the requirements of AS 1940

Ethanol (m3) 17,300 Bunded tank conforming to the requirements of AS 1940

Ferrous sulphate (t) 120 Dedicated, bunded reagents yard as per existing practice

Flocculant (t) 8,800 Bunded tank

Flotation modifier (t) 1,000 Dedicated, bunded reagents yard as per existing practice

Frother (t) 1,950 Dedicated, bunded reagents yard as per existing practice

Fuel oil (kL)1 14,000 Bunded tank conforming to the requirements of AS 1940

Liquid oxygen (t) 5,000 Above ground bullet tanks

Liquid petroleum gas (kL)1 32,000 Above ground bullet tanks

Natural gas (t)1 45,000 Above ground bullet tanks

Nitric acid (t) 150 Bulk containers stored in a dedicated bunded and undercover area

Promoter (t) 2,000 Dedicated, bunded reagents yard as per existing practice

Silica (Flux) (t) 56,000 Storage of pre-strip sand to be determined, but likely to be within the existing quarry, with intermediate storage in a stockpile

Soda ash (t) 6,700 Dedicated, bunded reagents yard as per existing practice

Sodaberg electrode paste (t) 410 Dedicated, bunded reagents yard as per existing practice

Sodium chlorate (t) 63,900 Dedicated, bunded reagents yard as per existing practice

Sodium cyanide pellets (t) 410 Bulk containers stored in a dedicated bunded and undercover area

Solvent extraction modifier (m3) 680 Stored in bulk containers within a dedicated bunded area

Sulphur (t) 1,720,000 Bunded and wind disruptive stockpile enclosure

Uranium extractant (Amine) (t) 270 Stored in bulk containers within a dedicated bunded area

Xanthate (t) 2,000 Dedicated, bunded reagents yard as per existing practice

Zinc (t) 115 Bulk containers stored in a dedicated bunded and undercover area

1 The expanded smelter may use natural gas in preference to diesel, LPG and fuel oil. Natural gas, LPG, diesel and fuel oil figures are ‘worst case’ maximum values.


5.5.6 taiLings storage faciLity

The design of the TSF is described below and in Appendix F1.

General waste management is discussed in Section 5.6.

overview

Tailings generated after the uranium and copper have been

extracted in the new hydrometallurgical plant would be

disposed of in a new TSF. Material from the countercurrent

decantation process within the new hydrometallurgical plant

would be directed to a new tailings disposal facility at a solids

concentration of around 55%. Tailings from the existing

metallurgical plant would also be directed to the new tailings

disposal facility, the combined tailings having a solids

concentration of around 52–55% solids.

The new TSF cells would be a refinement of the existing TSF

design which has been operating for 20 years, modified to make

use of both the experience gained in the operation of the

existing cells and the different types and volumes of

construction materials available.

Each of the proposed TSF cells would be approximately 400 ha

in tailings surface area, and eight cells would be required to

manage the additional tailings and water throughput. Area for

an additional cell would be allocated as a contingency in the

event of unforseen issues such as a positive water balance,

plant failures or extreme rainfall events. The area and design of

the TSF cells proposed would avoid the need to construct new

evaporation ponds to manage such events. An additional area

would also be disturbed to construct tailings walls, roadways

and infrastructure corridors.

The design of the TSF walls and the existing ‘upstream raise’

methodology would change. Using mine rock generated from

the open pit mine (which would otherwise be stockpiled in

the RSF), would allow the TSF cells to be designed with greater

stability in a ‘centreline raise’ arrangement, and to greater

heights than currently permissible. This method is detailed

further in the following sections.

Other design features have been proposed to improve the

management of acidic liquor. These include the use of a rock

ring wall within each cell, together with additional liquor

seepage control measures. These measures, together with the

additional cell area and the thickening of flotation tailings

within the new concentrator plant, would negate the need for

additional evaporation ponds and may allow the existing

evaporation ponds to be removed over time (see Chapter 15,

Terrestrial Ecology, for further information regarding fauna

interaction with the TSF). Covered balance ponds would also be

constructed to facilitate the transfer of acidic liquor from the

TSF cells back to the metallurgical plant, and to provide

additional surge liquor capacity to manage seasonal variation in

the water balance and high rainfall events.

TSF cells would be constructed throughout the development

phases, commencing with three TSF cells and two balance

ponds and finishing with eight or nine cells and four balance

ponds around Year 11.

context

Tailings storage facilities are used by mining and minerals

processing operations throughout the world. The annual

deposition rates of some of the world’s TSFs are presented in

Table 5.15.

Design

The main design features of the proposed TSF at Olympic Dam

are listed in Table 5.16 (the values provided are indicative and

may change as required during detailed design). Design

information is presented in Appendix F1, and summarised in the

following sections. Appendix F1 also discusses the key design

criteria and the various alternatives that were investigated

(see also Chapter 4, Project Alternatives).

TSF layout, geometry and key infrastructureThe number of TSF cells proposed and the rate of expansion are

described in the overview to this section, and shown in

Figure 5.6a and 5.6b. The major components of TSF cells are

shown in Figure 5.22 and further detailed in Figure 5.23.

A cross-section of the proposed TSF wall is shown in

Figure 5.22, detailing both the indicative construction sequence

and the components of the wall design.

The proposed TSF cells introduce a small central decant pond

(approximately 300 m x 300 m) within a flow-through rock filter

wall (see Figure 5.22) to maximise operational control of the

free liquor. The central decant facility also provides the

opportunity to restrict access (e.g. netting or similar) to the free

liquor and reduce fauna interaction with the TSF (see Chapter

15, Terrestrial Ecology). The flow-through wall also allows the

decant pond to be maintained centrally over the TSF seepage

control features, which are described below and illustrated in

Figures 5.22 and 5.23.

A 1.5 mm HDPE liner would extend over an area •

approximately 400 m x 400 m. The central pond would be

positioned above this area, allowing an additional 100 m of

liner outside of the decant pond.

The design ensures that all water inputs can be contained •

within the TSF with no potential for overtopping. At any

point in time, there is more than 4 m freeboard above the

water level that would occur after the Probable Maximum

Flood (PMF) event. The balance ponds would also be

designed with sufficient freeboard to accommodate the PMF

and ANCOLD (1999) guidelines without overtopping.

Seepage control measures would be implemented during •

each cell start-up process to minimise the ponding of liquor

on bare ground until such time as the tailings consolidated

to form an effective liner or barrier. These seepage control

measures would include constructing temporary divider

walls to enable rapid covering of the TSF floor, and

infrastructure to remove decant liquor from the edges of the

temporary area to the lined central decant area, where it

would be evaporated. These measures successfully limited

seepage when the existing TSF cell 4 was commissioned.


5

table 5.16 indicative features of the proposed tsf


Additional solids disposal rate (Mtpa) 58

Facility operating life (years) 40+

Number of TSF cells1 8 + 1

Design type Paddock style with centreline raise using mine rock walls and central decants

Deposition solids concentration (%) 52–55

Maximum rate of rise for tailings (m/annum) 2

Dry density of stored tailings (t/m3) 1.7

Final height (m) 65

Embankment slope angle (degrees) 25

Estimated height of starter embankment (average) (m) 10

Estimated TSF wall raise height (m) 10

Crest width of external walls (m) 10

Area of central decant pond (ha/cell) 9

Rate of acidic liquor return to the metallurgical plant at 72 Mtpa ore (ML/d) 24

Area of balance ponds (ha) 60

Depth of balance ponds (m) 10

Estimated final footprint – including contingency cell (ha) 4,400

1 The indicative number of TSF cells required for the management of the tailings and acidic liquor is eight. However, an additional cell has been allowed as a contingency in the event of unforseen issues such as plant failures or extreme rainfall events.

table 5.15 proposed olympic Dam tsf annual deposition rate compared to rates at other metallurgical facilities1

mine company country/australian state

type of tsf facility contains radioactive

material

annual deposition rate

(mtpa)

Escondida BHP Billiton Group (57.5%)

Rio Tinto (30%)

Mitsubishi (10%)

IFC (2.5%)

Chile Contained in a natural depression with a dam wall at one end

No 82

Olympic Dam – combined operations

BHP Billiton South Australia Paddock, centreline raise with central decant

Yes 69.6

Collahuasi Xstrata Chile Contained in a natural depression with a dam wall at one end

No 41

Rössing Rio Tinto Namibia Paddock, upstream raise Yes 14

Ernest Henry Xstrata Queensland ‘Turkeys nest’ style with upstream mine rock walls

No 9.9

Olympic Dam – existing operation

BHP Billiton South Australia Paddock, upstream raise Yes 9.8

Prominent Hill OZ Minerals South Australia Integrated waste landform with central decant

No 7.9

Century Zinc Zinifex Queensland Contained in valley with dam wall at one end

No 4.2

ERA Ranger Rio Tinto Northern Territory Initially to paddock tailings cells, now returned to Pit 1 depression

Yes 2

Langer-Heinrich Paladin Resources Namibia In-pit disposal Yes 0.9

Narbalek Queensland Minerals Northern Territory Tailings returned to old pit using sub-aqueous deposition

Yes 0.6

McClean Lake Areva Canada In-pit disposal Yes 0.2

1 Sourced from Uranium Equities 2008.

Olym

pic Dam


ental Impact Statem

ent 2009130

Free-draining rock

Depositedtailings beach

Sand drainagelayer over liner

Central decant pond

To balance ponds

Consolidatedtailings

10 m (min)crest width

400 x 400 m square 1.5 mm HDPE lined decant area

65 m

SECTION A - A’

Central decant surrounded byrock fill with diesel pumps forunderdrainage and decant removal

300 x 300 m square flow through rock wall to control pool position and size and

support fauna restriction systems

Sand pads protect liner under rockfill

SEE FILTER DRAINDETAIL ON FIGURE 5.23

SEE CENTRAL DECANTDRAIN DETAIL ONFIGURE 5.23

SEE WALL DETAILON FIGURE 5.23

To processing plant

Sand padsprotect liner

under rock fill

Perimeter bund for containmentof water during commissioning Shaped to fall

to centre Strip drains and conveyance outlet pipes

~2,000 mA A’

Mine rockperimeterembankment

Dry tailingsbeach lengthabout 850 m

Section shown below

~400 x 400 msquare 1.5 mmHDPE liner

Filter drain aboveHDPE liner

Decant accessembankment

Central tower forcollecting and

pumping decant

~300 x 300 msquare rock flow

through ring wallTailingsstoragefacility

Balanceponds

TSF cell shown in

detail adjacent

Figure 5.22 Plan view and cross-section of a cell within the proposed tailings storage facility


5

Vertical decant outlet riser (slotted)

Tailings

Detail locations are shown on Figure 5.22

Free-draining rock

Tailings

Final position ofdownstream toe

65 m

Downstream toedrain

Clayey silty sand – usedas continuous basal drain

Upstream toedrain

WALL DETAIL

10 m

CENTRAL DECANT DRAIN DETAIL

FILTER DRAIN DETAIL

Water level

Limestone

Sand fill

In-situ sand

1.5 mm HDPE liner

Liner end cast into base Reinforced concrete tower base

Drainage through sandinto decant tower

Original ground level

Drainage through rockfill into decant tower

Sand filled decant tower (slotted pipe)

Drainage fromfilter drain

Vertical underdrainage outlet riser (unslotted)

500 mm

1.5 mmHDPE liner

3 m

Floor shaped tofall to centre

To centraldecant tower

Strip drains and conveyance piping

Sand bedding to liner where required

300 to700 msand

200 mmGeofabric wrap

Gradedfilter drain

Gravelcover

Very low permeabilityundisturbed Andamooka Limestone

Run-of-minecompetent rock

Class C or D

Figure 5.23 Seepage control and design details for the proposed tailings storage facility at Year 40


A layer of dune sand on top of the HDPE liner would form a •

base drain. The sand layer may eventually become clogged

by fine tailings, but it would assist with consolidation of the

fine tailings and provide an effective low permeability layer

above the liner. The sand layer would also act as a

protective cover to the liner.

A filter drain would be installed above the liner to act as a •

permanent drain to recover liquor back to the decant ponds

prior to transfer to the balance ponds (see below).

A number of balance ponds would be constructed, allowing

liquor to be decanted from the TSF cells and either returned to

the metallurgical process or directed to the tailings disposal

circuit to be returned to the TSF. The balance ponds would be

about 60 ha in total area, and would be covered to restrict

fauna access and lined to minimise seepage.

Geotechnical stabilityThe stability of the proposed TSF (i.e. a centre raised rock fill

design, with a slope angle of 25 degrees and assessed at a

height of 40 m and 80 m) was assessed using methods

described in the ANCOLD standards (ANCOLD 1999), taking into

account the necessary safety factors for high pool (exceeding

the minimum freeboard requirements), earthquake loading and

normal operation. The factor of safety ratings of the proposed

designs meets or exceeds the ANCOLD criteria as shown in

Table 5.17.

Tailings geochemistryThe geochemistry and radiological properties of the new

tailings are expected to be similar to the current tailings, with

a pH on deposition of about 1.5 (see Table 5.18 to Table 5.21).

Further information regarding the geochemical properties of

the tailings as they relate to seepage is described in Chapter 12,

Groundwater.

construction phase

During the initial development, three new TSF cells would be

constructed, together with two balance ponds. The vegetation

and sand dunes would be removed from the footprint of each

TSF cell prior to construction. TSF walls would generally be built

in 10 m lifts, with one cell taken off-line during wall raising,

then recommissioned upon completion of the 10 m lift. It is

expected that wall raising would take about one year to

complete per cell. Initial TSF walls would be constructed to

different heights to establish a sequence that would aid in

scheduling subsequent cell decommissioning and wall raising

activities. TSF cell walls would be constructed of class C or D

mine rock (see Section 5.4.6 for details).

Subsequent development phases would involve the construction

of an additional five or six TSF cells and two balance ponds.

As previously discussed, the starting heights for these would

be staggered.

operation phase

During operation, tailings would be deposited to all but one of

the TSF cells at any given time (the other being taken off-line to

raise walls). Deposition would be via spigots mounted on the

edge of the cells, as occurs with the existing TSF. The tailings

would be deposited in thin layers up to a maximum of 2 m in

depth per annum when fully dried.

Liquor that does not evaporate on the beaches (the decant

liquor) would flow through the central flow-through rock wall

into the decant pond, and be directed for further treatment by

one of two alternative methods:

to the covered TSF balance ponds, then recycled to the •

metallurgical plant for use as dilution liquor following

flotation tailings thickening within the new concentrator

plant

recirculated, via the tailings disposal circuit, to the TSF cells •

to obtain additional evaporation on the TSF beach areas.

The treatment path would be determined by the volume of

decant liquor available and by the demand for acidic liquor in

the metallurgical plant.

5.5.7 integration with the existing processing

faciLities

The interaction of the new metallurgical plant and the existing

metallurgical plant has previously been discussed throughout

Section 5.5, and is summarised below:

the existing concentrate leach circuit would be expanded•

the existing smelter and associated infrastructure would be •

expanded

the existing electrorefining tank house would be expanded •

the existing precious metals recovery plant would be •

optimised

a new acid plant would be added to the existing smelter•

pipelines would be installed to transport copper concentrate •

from the new concentrator plant to the expanded

concentrate leach facility

table 5.17 factor of safety for the proposed tsf compared to ancoLD criteria

Loading condition factor of safety

ancoLD criteria proposed tsf

Normal operation 1.5 1.53

Steady state seepage (high pool) 1.3 1.31

Earthquake 1.1 1.20


5

table 5.18 chemical constituents of existing tailings solids

constituent concentration

Aluminium 4.34%

Arsenic 30–150 ppm

Barium 0.6%

Calcium 1.5%

Copper 0.08%

Fluorine 1.0%

Iron 29.6%

Lead 40–120 ppm

Magnesium 0.22%

Manganese 80–170 ppm

Potassium 2.6%

Sodium 0.21%

Uranium 65–274 ppm

table 5.19 chemical properties of existing tailings liquor

constituent concentration (mg/L)

Aluminium 9,100

Calcium 1,000

Chloride 5,500

Copper 2,000

Cyanide Not detectable

Fluoride 2,000–5,000

Iron 40,000

Lead 6

Magnesium 500–5,000

Potassium 350–6,000

Silica 2,000

Sodium 5,000–24,000

Sulphate 135,000

Sulphuric acid 11,900

Thorium 17

Uranium oxide 130

Free acidity 8,000–15,000

table 5.20 radiological properties of existing tailings solids

radionuclide activity (Bq/g)

Lead-210 5.3

Polonium-210 6.4

Radium-226 5.8

Thorium-230 4.5

Uranium-238 1.3

table 5.21 radiological properties of existing tailings liquor

radionuclide activity (Bq/L)

Lead-210 150–250

Polonium-210 30–100

Radium-226 3–10

Thorium-230 1,200–2,400

Uranium-238 250–1,200

a tailings pipeline would be installed to transport tailings •

from the existing metallurgical plant to a new tailings

disposal facility within the new metallurgical plant.

The other major interaction relates to the import and export of

materials and products to and from the operation. A new rail

terminal would be constructed to import the reagents necessary

to process the ore, and export the refined metal products,

uranium oxide and concentrate. Reagents would generally be

delivered by rail then distributed between the proposed and

existing metallurgical plants by either loaders or trucks.

Suitable road access to deliver bulk goods to the existing

metallurgical plant would need to be provided. Until the rail line

is constructed, reagents would continue to be imported by truck

as per the existing operation.

5.6 on-site inDustriaL anD generaL waste management

5.6.1 overview

The management of industrial waste generated on-site from the

mining and processing operations would largely follow the

existing site practices, controlled through the site EM Program

(see Chapter 2, Existing Operation, and Chapter 24,

Environmental Management Framework, for further

information). A new waste management facility complying with

relevant legislation would be constructed, incorporating a new

waste transfer station, a new landfill site and new areas for

storing materials that are to be reused or recycled (see

Figure 5.8 for location of proposed landfill zone). Off-site

wastes are discussed further in Section 5.10.2.

5.6.2 generaL wastes

The volumes of industrial and general wastes arising from the

expanded operation are summarised in Table 5.22 and

illustrated in Figure 5.24. Tyres, sewage, hazardous and low

level radioactive wastes are discussed in greater detail in the

following sections.

new waste management facility

An area of around 560,000 m2 has been assigned for the future

development of the waste management facility (see Figure 5.8).

This would be suitable for around 60 years of operational life at

the predicted waste generation rates, and assuming a 15 m

maximum landfill height plus 10% additional height for a

landfill cover (equating to an available volume of around

7.5 million m3). The new waste management facility would

consist of:

a transfer station (this may continue to be the existing •

transfer station)

a recyclable materials store located near the rail head•

a general waste landfill facility for industrial wastes with a •

small content of putrescibles (2.5% during the construction

phase and 0.5% during the operation phase). Cover to the

landfill would be provided on a daily basis with construction

of the waste cells in accordance with EPA guidelines.


table 5.22 indicative annual general waste generation rates (excluding tyres, sewage, hazardous and low-level radioactive wastes)

waste type expanded operation (construction phase)

expanded operation (ongoing operation)

indicative management practices

volume (m3)

mass (t)

volume (m3)

mass (t)

Plastic 61,000 3,000 38,000 2,000 Bulk containers and HDPE pipe would be reused and/or recycled. Miscellaneous plastic may be sorted and recycled, subject to market availability and transport cost, otherwise would be directed to landfill

Wood 16,000 3,000 10,000 1,700 Pallets would be reused where possible, with other timber wastes stockpiled and chipped for use as mulch

Paper/cardboard 29,500 1,500 18,000 900 The existing paper and cardboard recycling schemes would be expanded to increase the volume of paper and cardboard recycled

Steel 70,500 9,500 44,000 5,700 The current practice of recycling all ferrous metals would continue, subject to the materials meeting the surface radiation limit for off-site transport. Should material not meet these limits, it would remain on-site until such time as the limits were met

Aluminium 1,200 200 700 100 The current practice of recycling all non-ferrous metals would continue, subject to the materials meeting the surface radiation limit for off-site transport. Should material not meet these limits, it would remain on-site until such time as the limits were met

Putrescibles 1,200 500 700 300 Would be disposed of to the on-site landfill

Filters 1,500 200 1000 100 Air filters would continue to be cleaned and reused (up to five times) before being disposed of to landfill. Oil filters would be drained of oil and the metal casing recycled

Inert materials 10,000 200 6,000 100 Clean fill and concrete would be preferentially used as a construction material (e.g. road base) where possible, or stockpiled within the waste management centre or disposed of to landfill

Rubber 3,500 700 2,200 500 The current practice of reusing conveyor belt for fencing and sandhill stabilisation would continue. It may be possible to treat the surplus rubber as part of the tyre recycling scheme

total 194,400 18,800 120,600 11,400

Waste by massWaste by volume

Tyres

Steel

Plastic

Paper/cardboard

Wood

Inert materials

Rubber (excluding tyres)

Filters

Aluminium

Putrescibles

Low level radioactive waste

23%

36%

42%

29%

10%

9%

4.5%

2%

1.5%

20%

10%

5%3%

1.5%0.5% 0.5%

Figure 5.24 Predicted waste generation by type


5

5.6.3 tyres

The most significant change to the volumes of waste generated

from the proposed expansion would be the considerable

increase in rubber tyres, from the existing rate of around 25 tpa

to about 8,090 tpa. This is associated principally with the tyres

used on haul trucks required for the open pit operation (see

Table 5.23).

Several options for managing used tyres are currently being

investigated. The hierarchy of preferred practice adopted for

the expanded operation is to:

reduce the volumes of tyres requiring management by •

implementing programs to increase the life of tyres

retread or repair, where possible•

use waste tyres for industrial purposes such as berms, road •

demarcation and fencing

treat waste tyres using energy recovery technologies such as •

incineration, co-combustion, tyre-derived fuel, pyrolysis,

gasification, shredding and granulation

disposal in RSF in a documented location.•

While the disposal of waste tyres in the RSF is accepted practice

within the mining industry, if not properly managed it may lead

to stability issues in the RSF if the tyres are stacked too high,

metal leaching if the tyres are shredded before disposal, or it

may create a potential fire hazard if the tyres are not covered

with inert material. Investigations facilitated by BHP Billiton

into the recycling of tyres, including a trial for recycling a haul

truck tyre, are showing promising results with the tyre steel

being successfully separated and the production of rebonded

rubber that has physical characteristics practically identical to

the vulcanised rubber that made up the original tyre.

In the event that the investigations do not provide a recycling

solution for the volume of Olympic Dam used tyres, and disposal

in the RSF is required, appropriate management practices to

mitigate the above-mentioned risks would be applied.

5.6.4 sewage management

The sewage treatment plant handles the collection and pumping

of raw sewage, treatment of raw sewage and the disposal of

effluent from the treatment plant. The proposed sewage

treatment plant, to provide for 2,500 people, would be a

proprietary packaged plant located to the north of the

concentrator. Class B treated water is expected to be produced

in accordance with water recycling guidelines, and would be

recycled into appropriate process uses.

5.6.5 Low-LeveL raDioactive waste (incLuDing

LaBoratory waste)

Low-level radioactive waste would continue to be produced at

the expanded operation. This waste would generally comprise

laboratory waste (about 8 m3 per annum) and used personnal

protective equipment from workers within the uranium packing

compound (about 40 m3 per annum).

Low-level radioactive waste is currently disposed of in the TSF

and this practice would continue for the expanded operation.

Disposal of low-level radioactive waste during the operation of

the expanded facility would be consistent with relevant codes

and legislation, including the provisions of the Code of Practice

and Safety Guide for Radiation Protection and Radioactive

Waste Management in Mining and Mineral Processing 2005.

Chapter 22, Health and Safety, provides further information on

the management of radiation at Olympic Dam.

5.6.6 hazarDous wastes

The existing metallurgical process produces some hazardous

materials, and these would continue to be produced for the

expanded metallurgical plant. In general, any hazardous

materials produced would be recycled wherever possible, as

occurs with the existing operation. The hazardous wastes that

would be recycled are:

Slag, which would be forwarded to a slag re-milling circuit •

within the metallurgical plant where it would be ground to a

fine slurry before passing through a flotation circuit and

either passing through the hydrometallurgical plant to be

deposited to the TSF, or through the feed preparation plant

where it would be blended with other copper concentrates

and fed into the smelter.

Smelter acidic effluent, which would be directed to the •

hydrometallurgical plant (where the acid would supplement

the leaching process), or to the TSF.

Waste hydrocarbons, which would be collected in a •

dedicated area of the waste management centre. The waste

oils could be used in explosives produced on-site, or could

be either used directly in the smelter furnaces, following the

implementation of suitable modifications to furnace burners,

or be transferred to Adelaide to be converted into fuel oils

for use in the existing unmodified furnaces. Should the

on-site furnaces be converted to natural gas, the oil or

converted fuel oils could be used within other furnaces and

kilns in South Australia.

table 5.23 indicative tyre generation rates for the proposed expansion

type of tyre tyres per annum tonnes per tyre type tonnes per annum

Haul trucks – large 1,300 5.3 6,890

Haul trucks – medium/small 200 2.8 560

Ancillary heavy equipment 320 1.5 480

Light vehicles 1,600 0.1 160

rounded total 3,420 – 8,090


Paints, thinners and solvents, of which about 30,000 litres •

per annum would be expected to be generated. These are

currently recycled where possible, or transported to

Adelaide for disposal in a registered landfill. Future solvent

waste could be used as a heat source for on-site furnaces, or

may continue to be disposed of in a registered landfill.

Hazardous wastes for which there is no favourable recycling

option would be collected and disposed of in accordance with

applicable regulations and legislation.

Acid plant catalyst, used within the acid plant gas converters, is

one such waste. These typically contain about 6–9% vanadium

pentoxide, and the expanded operation would have an installed

capacity of around 4.1 ML of catalyst. Routine maintenance is

undertaken to screen the fine catalyst material from the gas

converter beds, with the first bed being screened every three

years, the second bed every six years and the third and fourth

beds every nine to twelve years. On average, such screening is

expected to generate around 225,000 litres of catalyst fines

every three years, which would initially be transferred to lined

steel drums and stockpiled prior to disposal or recycling.

Options for recycling catalyst fines (to either the supplier or a

vanadium refining operation) will continue to be investigated

up until the fines are generated. Historically, however, recycling

has not proved to be viable in Australia. If a suitable recycling

option is not found, the catalyst fines would be disposed of in

trenches excavated into the TSF and their location documented.

5.7 water suppLy

5.7.1 overview

The demand for water of various qualities would increase

during construction and operation of the proposed expansion.

The most significant areas of increased demand are associated

with the need for low-quality water for dust suppression within

the new open pit mine, increased process and demineralised

water use associated with the new metallurgical plant, and

increased potable water demand required from the expansion of

Roxby Downs and the operation of Hiltaba Village.

The construction of infrastructure associated with the proposed

expansion would also require water, specifically for use in

compaction activities, concrete manufacture, dust suppression

and hydro-testing of the water supply and gas supply pipelines.

Saline water would be used where practicable to reduce the

volume of process and potable water required.

Water for the proposed expansion would be obtained from a

number of sources, depending on the quality of water required

and where the water would be used. During construction of

off-site infrastructure such as the rail line and the water and

gas supply pipelines, low-quality water would be sourced from

existing or new groundwater wells along the infrastructure

corridors. Higher-quality water, for use in construction camps or

for hydro-testing pipelines, would be sourced from either the

existing on-site desalination plant, the proposed new coastal

desalination plant or from the existing state water supply

network, depending on timing and where the water would be

used. The demand for on-site construction water would be met

through a combination of process or potable water from the

existing GAB supply source if high-quality water is desired, or

from wellfields should low-quality water be required.

The demand for operational water would be met through the

construction and operation of a coastal desalination plant

located at Point Lowly (see Figure 5.4) and an associated water

supply pipeline (see Figure 5.4) combined with abstraction from

a number of saline aquifers in the SML and the broader

Stuart Shelf (see Figure 5.25). The desalination plant would

produce potable quality water, which would either be used

on-site as is, or desalinated on-site to produce demineralised

water. Water required for dust suppression during the operation

of the open pit mine would be sourced from a combination of

saline water extracted from the mine depressurisation activities

or from saline wellfields.

The existing underground mine and metallurgical plant would

continue to source process, potable and demineralised water

from the GAB, via the on-site desalination plant.

5.7.2 summary of water DemanD

A summary of the water demand and supply source for the

construction and operation of the proposed expansion is

presented in Tables 5.24 to 5.27. Demand fluctuates with

seasonal and operational variations (e.g. maintenance

shutdowns) and, as a consequence, the volumes presented may

vary in any given year.

table 5.24 indicative water source and demand during construction (olympic Dam site development)

source Demand (mL/d) Description

potable

Great Artesian Basin (GAB) and local saline wellfields

up to 7 The current demand from the existing GAB Wellfields A and B averages 37 ML/d. The current licence limit is based on drawdown, extrapolated to an extraction rate of about 42 ML/d. Further extraction from Wellfield B, under South Australian Government approvals, would be used to supply potable water during the construction phase, with any additional needs being met through on-site desalination of water extracted from local saline wellfields

saline

Mine depressurisation and saline aquifer extraction

25 This water would be obtained from depressurising the open pit (about 20%) and extraction from production wells associated with the fractured rock aquifers in the vicinity of the mine area (about 80%)


5

table 5.25 indicative water source and demand during construction (off-site infrastructure development)

infrastructure development approximate total demand

(mL)

source and description

Water supply pipeline 485–590 This is required for hydrostatic testing of the pipeline (about 85–90 ML), first flush testing (about 400–500 ML), and small volumes used for dust suppression and concrete manufacture. The water for hydrostatic testing and concrete would be supplied either through water generated during commissioning of the Point Lowly desalination plant, through the existing on-site desalination plant, through the state potable water supply network, or a combination of these. Water used for dust suppression would be sourced from saline aquifers

Desalination plant 100

This is required for earthworks, dust suppression and concrete manufacture. With the exception of concrete manufacture, water would be sourced from saline aquifers. Water for concrete manufacture would come from either the existing on-site desalination plant or the state potable water supply network

Transmission line 50

Gas supply pipeline 20

Rail line 500

Pimba intermodal facility 20

Roadworks 200

Port – Darwin 20

Port – Outer Harbor 20

Port – Landing facility 5

Airport 20

Roxby Downs 200

Hiltaba Village 300

total 1,940–2,045

table 5.26 indicative water demand and source during operation of the combined operation

area of demand average daily

demand (mL)

source and description

Existing metallurgical plant 36 GAB wellfield

Existing underground mine 1 GAB wellfield

New metallurgical plant 151 Water would be sourced from the proposed coastal desalination plant and used directly within the plant. Further treatment of some water would be undertaken at the on-site desalination plant to meet the new metallurgical plant demineralised water demand

Open pit mine and associated facilities 7

Roxby Downs residential growth 5 Potable water for the expanded operation would be sourced from the proposed coastal desalination plant and piped directly to the townships for distribution. Off-site infrastructure operational water demand, including the water needs for the airport, pumping stations, transmission lines, gas pipeline and the landing facility, would be expected to total less than 1 ML/d

Hiltaba Village 2

Regional users including Andamooka 1

Dust suppression and other engineering needs

25 Sourced from the coastal desalination plant. Alternatively, saline water would be used, originating from either the open pit mine depressurisation wells, or from saline wellfields within the Stuart Shelf groundwater system

total 228

table 5.27 indicative water supply during operation of the combined operation

supply average daily demand (mL)

Existing GAB Wellfields A and B 42

Coastal desalination plant 1861

total 228

1 25 ML/d may be sourced from saline groundwater and mine depressurisation.

5.7.3 proposeD expansion water BaLance

An indicative water balance for the proposed expansion,

following the final development phase, has been developed,

and is illustrated in Figure 5.26.


OLYMPIC DAM

Andamooka

Roxby Downs

WhyallaPort Pirie

Roxby Downs

Port Augusta

Transfer tank

Trial injection well

Potential production well

Pipeline estimate

Trial saline pipeline




Rail alignment




EIS Study Area

Motherwell wellfield

Local saline wellfield0 2 4 6 8 10

km

Figure 5.25 Indicative locations of local and regional saline wells


5

GreatArtesian

Basin

Coastaldesalination

Open pitmine

Additionalmetallurgical plant

Tailingsstorage facility

Undergroundmine

EvaporationRetainedSeepage

* Subject to drawdown limit approvals

Existingmetallurgical plant

Salinewellfield

Minefacilities

Processstorage

RoxbyDowns

HiltabaVillage

Regionalusers

3 ML/d

34 ML/d

128 ML/d 24 ML/d

5 ML/d

5 ML/d151 ML/d1 ML/d36 ML/d

2 ML/d

1 ML/d

2 ML/d

5 ML/d 10 ML/d

203 ML/d

193 ML/d

161 ML/d25 ML/d

25 ML/d(Alternativesupply)

42 ML/d*

1 ML/d

Upto 15 ML/d(rainfall)

52 ML/d(evaporation)

3 ML/d(evaporation)

25 ML/d(evaporation)

83 ML/d62 ML/d

Figure 5.26 Indicative water balance for the combined operation


5.7.4 DesaLination pLant

overview

A coastal desalination plant would be constructed to supply

potable water to the new open pit mine, metallurgical plant and

associated infrastructure. The proposed plant would use reverse

osmosis to produce water from seawater extracted from the

Spencer Gulf. Seawater would be pumped through fine

membranes to produce low-salinity product water and

high-salinity return water. The return water would be a

combination of brine (which is about twice as salty as seawater)

and small quantities of anti-scalant chemical used to prevent

scale accumulating on the membranes of the plant (see Chapter

16, Marine Environment, for further discussions regarding the

potential environmental impacts associated with the discharge

of return water into the gulf). A conceptual layout of the

proposed coastal desalination plant is provided in Figure 5.27.

The proposed desalination plant would be constructed in

modules to allow a ramp-up in potable water production to

meet the increased demand of the proposed expansion as it

develops to 60 Mtpa of ore mined. Indicative features of the

plant are provided in Table 5.28.

The construction and operation of the desalination plant would

create additional demand for electricity, water and labour (see

Table 5.29).

table 5.28 indicative features of the proposed desalination plant


Method Reverse osmosis

Distance off-shore for intake pipe (m) >250

Diameter of the intake pipe (m) 3.0

Volume of seawater intake (ML/d) 6501

Salinity of seawater intake (nominal – g/L) 38–42

Peak volume of potable water produced for the proposed expansion (ML/d) 2001

Peak volume of potable water produced to replace River Murray supply (ML/d) 801

Distance off-shore for outfall pipe (m) >600

Diameter of outfall pipe (m) 2.1

Length of the return water dispersion structure (m) 200

Volume of return water (ML/d) 3701

Salinity of return water (g/L) 78

1 The data includes South Australian Government requirements and represents peak daily demand.

south australian government water supply

The development of a desalination plant at Point Lowly would

provide an opportunity for the South Australian Government to

deliver a new water supply to the Upper Spencer Gulf and the

Eyre Peninsula areas, replacing about 80 ML/d of water

currently pumped from the River Murray. Water produced for

the government’s needs would meet the Australian Drinking

Water Quality Guidelines 2004. This would require additional

water treatment modules within the proposed desalination

plant, with the desalinated water passing through additional

reverse osmosis membranes to achieve the required water

quality standard.

The assessment of the potential impacts of constructing and

operating the desalination plant on the marine environment

has been based on the total desalination plant throughput

(i.e. BHP Billiton’s peak requirement plus the government’s peak

requirement, see Table 5.30). The potential impacts of

constructing the government-managed water supply pipeline to

the existing state potable water network were also assessed.

Some additional infrastructure such as pump stations and water

storages may also be required to supplement the existing

government water supply network. An assessment of this

additional infrastructure has been undertaken and is presented

for completeness in Appendix F3. However, approval for these

ancillary facilities is not sought in the Draft EIS.

table 5.29 indicative major demands for the proposed desalination plant


Water demand during construction (ML) 100

Electricity consumption during operation (MWh per annum) 245,000

Percentage of electricity consumption to be met from renewable sources (%) 100

Peak construction/shutdown workforce 400

Ongoing operational workforce 30

Total land disturbance (ha) 29 + 121

1 12 ha is allocated for a temporary construction laydown area. This would be rehabilitated as necessary following completion of construction works.

Olym

pic Dam


ental Impact Statem

ent 2009141

5

Santos facilities

WeeroonaBay

Port Bonython Jetty

Point Lowly Lighthouse

Desalination plant area = 19.5 hectaresSantos facility area = 86.5 hectares

To Whyalla

Figure 5.27 Conceptual layout of the proposed coastal desalination plant


context

Water bodies such as Lake Eyre South and Lake Torrens are

within 200 km of Olympic Dam, but these are salt lakes that

rarely fill and only after heavy and prolonged rainfall. Olympic

Dam receives on average about 167 mm of rainfall per annum

and has a pan evaporation rate of approximately 3,000 mm

per annum.

The preferred option to supply fresh water for the proposed

expansion is a reverse osmosis desalination plant, located at

Point Lowly near Whyalla, about 320 km from Olympic Dam.

There were about 4,600 desalination plants operating

worldwide in 1985 (Al-Mutaz 1991), more than 7,500 in 1993

(California Coastal Commission 1993) and about 12,300

desalination plants in 147 countries in 2006 (Global Water

Intelligence 2006). Of the 12,300 desalination plants, about

1,460 are coastal desalination plants using reverse osmosis

technology and they are installed in around 96 countries,

divided into regions as shown in Figure 5.28. In comparison,

Australia currently produces relatively little desalinated water

(around one per cent of the world’s capacity); however, a

Figure 5.28 Seawater reverse osmosis desalination capacityby region

Source: Global Water Intelligence 2008

Middle East / Africa3,652 m3/d

(46%)

Europe2,027 m3/d

(26%)

Asia Pacific1,102 m3/d

(14%)

Americas1,063 m3/d

(14%)

Operational

Under construction

Proposed

Plant 1: 140 ML/dPlant 2: 125 ML/dPlant 3: 140 ML/d

10 ML/d

Perth

Siro Iron Project140 ML/d

Pilbara

Hobart

Darwin

Adelaide137 ML/d

Point Lowly280 ML/d

SydneyPlant 1: 250 ML/dPlant 2: 250 Ml/d

Gold Coast125 ML/d

Wonthaggi (Melbourne)411 ML/day

Alice Springs

Olympic Dam

Figure 5.29 Australian desalination plants

table 5.30 combined coastal desalination plant volumes

supply average daily demand (mL) Design capacity (mL/d)

Olympic Dam desalination plant 186 200

SA Government desalination plant 65 80

total 251 280

number of large-scale desalination plants are proposed or

under construction (see Figure 5.29).


5

Examples of reverse osmosis desalination plants of comparable

size are listed in Table 5.31.

Design

The major design features of the proposed desalination plant

are listed in Table 5.29. Figures 5.30 and 5.31 provide

conceptual drawings of the proposed plant design and the

locations of the associated intake and outfall pipes. The major

design features and a summary of the proposed desalination

process are discussed in the following sections and shown

in Figure 5.32.

table 5.31 examples of reverse osmosis desalination plants1

name country/state potable water produced (mL/d) stage of development

Mactaa Algeria 500 Proposed

Wonthaggi (Melbourne) Victoria 411 Under construction (completion expected 2010)

Hamriyah United Arab Emirates 364 Proposed

Istanbul Turkey 300–350 Proposed

Ashkelon Israel 330 Operational (2005)

Point Lowly South Australia 280 (includes 80 for SA Government)

Proposed

Ashdod, Soreq, Hadera Israel 274 each Under construction (completion expected 2012)

San Francisco Bay United States of America 270 Proposed

Sydney New South Wales 250 (expandable to 500) Under construction (completion expected 2009)

Port Qasim Pakistan 227 Proposed

Taweelah United Arab Emirates 225 Under construction (completion date unknown)

Jeddah Saudi Arabia 225 (expanding to 465) Operational (1984), expansion proposed

Ténès Algeria 200 Proposed

El Hamma Algeria 200 Operational (2005)

Rabigh Saudi Arabia 200 Under construction (completion date unknown)

Brisbane River (Brisbane) Queensland 200 Proposed

Calsbad, Huntington Beach, San Onofre (California)

United States of America 190 each Proposed

Jebel Ali N United Arab Emirates 182 Operational (unknown)

Qidfa United Arab Emirates 170 Operational (2004)

Lima Peru 2 x 150 Proposed

Sino Iron Project (Pilbara) Western Australia 140 Under construction (completion expected 2009)

Binningup (Perth) Western Australia 140 Under construction (completion expected 2011)

Port Stanvac (Adelaide) South Australia 140 Proposed

Tuas Singapore 136 Operational (2005)

Shuwaikh Kuwait 136 Proposed

Kwinana (Perth) Western Australia 130–143.7 Operational (2006)

Tugun (Gold Coast) Queensland 125 Under construction (completion expected 2009)

Tampa Bay United States of America 95 (proposed expansion to 132) Operational (2003)

Escondida Chile 45 Operational

Olympic Dam – current South Australia 14 Operational (1988)

Penneshaw South Australia 0.3 Operational (1999)

1 Sourced from Global Water Intelligence, 2008.


WeeroonaBay Santos

facilities

-15

-5

-20

-10

-2

-20

-15

-2

-20

-10

-15

-20

-20

-15

-5

-10

-2

0 0.5 1km

Port BonythonJetty

Preferred intake pipe alignment

Preferred outfall pipe alignment

Water pipeline alignment to Olympic Dam

SA Government pipeline to existing network

Transmission line alignment to existing network

Point Lowly

Whyalla

Port Augusta

PointLowly

Proposeddesalination plant

Pumpstation

Indicative layout

Reverseosmosis

Futuretank

Filteredwatertank Optional

stage 2filter

Future filtration plant

Single stagefiltration

plant

Optionalsludge

dewateringplant

Productstorage

ProductstorageElectrical

switchyard

LagoonLagoon

Lagoon Lagoon

Storagepond

Future reverse osmosis

Pumpstation

Perm

eate

sto

rag

e

Sto

rmw

ater

Lim

e

Op

tio

nal

futu

re r

o

Figure 5.30 Indicative configuration and infrastructure alignments for the proposed desalination plant

Olym

pic Dam


ental Impact Statem

ent 2009145

5

DESALINATION PLANT IN

TAKE STRUCTURE

OU

TFALL STRUCTURE DESIG

N

Profile of diffuser pipe

Risersection

200 metres

5m

10m

15m

20m

Aquaculture leases

LighthousePoint Lowly

Water depth

Strongcurrent zone

Returnwater

pipeline

Area ofdischargeSeafloor

Diffuser

Riser

Seawaterintake structure

Buried intake pipeDesalination

plant

Santos facilityCoastal homes

Pump station

Port BonythonJetty

0 m

10 m

20 m

Figure 5.31 Conceptual layout of the proposed desalination plant and intake/outfall infrastructure at Point Lowly

Olym

pic Dam


ental Impact Statem

ent 2009146

Seawaterintake structure

Upper Spencer Gulf

Intake screening facility

Sand filtration plant

Cartridge filtration plantProductstorage

(anti-scalants)

Reverseosmosis

membranes

Lime,carbon dioxide, caustic soda andfluoride dosing

Productstoragepond

Lagoons Stormwaterpond Electrical

switchyard

Indicative desalination plant layout

Schematic of proposed process

Administration Maintenance

Watertanks

Pumpstation

Processwater toOlympic

Dam

Potablewater to

EyrePeninsula

Return water

Backwashing

Dewatering

Return water pipeline Diffuser

8

1

1

2

9

3

6 6

4

3

5

5

6

8

7

7

4

2

9

Figure 5.32 Proposed desalination process


5

Intake sump and pipeA reinforced concrete sump of about 15 m x 15 m would be

constructed near the shore to a depth of about 10 m so that

intake seawater can gravitate to the sump. A contingency of

around 0.9 m was added to the wave elevation calculations,

fundamental to the seawater intake design, to account for

potential sea level rise associated with climate change. A small,

enclosed building would be constructed over the sump and

seawater would be pumped in a buried water pipeline to the

desalination plant. The sump would include secondary intake

screening, flow stabilisers and either a submersible pumping

well or a dry pumping well. Chlorine dosing systems (to inhibit

fouling of the intake pipe) would be placed as close to the

intake as possible. These systems would be installed at the

same time as the intake structure. Chlorine dosing would occur

intermittently to prevent marine growths and the residual

chlorine would be removed by chemical scavenging using

sodium metabisulphite or neutralisation before the seawater

is desalinated.

The end of the intake pipe would be fitted with a bar screen

and intake structure (see Figure 5.31). The intake structure

would be designed to limit flow velocities to about 0.2 m/s.

The inflow rate from the structure would average about

560 ML/d, with 650 ML/d at peak demand. The average salinity

of the intake water is expected to be between 38–42 g/L

(seasonally dependent).

Desalination plantSeawater dosed with acid, coagulant and/or a polymer would

be directed through mixing tanks and a deep-bed sand filter,

which operate just like a domestic pool filter. Fine particles

would be captured in the filter and removed during periodic

backwashing, which would occur once per day. Solids from the

backwash water would be removed and disposed of on land.

Product from the media filters would be directed to cartridge

filters. The filters contain disposable cylindrical elements, not

unlike those used in household water filters. Anti-scalants

(phosphates, organophosphonates or polymers) are then added

to control the scaling potential of the water and these are

discharged to Upper Spencer Gulf with the concentrated

seawater (collectively termed return water).

High-pressure feed pumps are used to create a sufficiently high

water pressure to drive the reverse osmosis process. Seawater

would be pumped to a number of membrane elements, with

around 45% of the water passing through the membrane to

produce low-salinity product water. The remaining water, and

the salt rejected by the membranes, forms a concentrate stream

with a salinity of around double that of the seawater.

Low-salinity (about 300 mg/L salt) product water would be

dosed with lime, carbon dioxide, caustic soda, chlorine and

possibly fluoride, and held in storage ready to be pumped to

Olympic Dam. The return water would be discharged via a

diffuser into Upper Spencer Gulf.

Outfall pipeThe outfall pipe would be a 2.1 m diameter glass-reinforced

plastic pipe with the end of the pipe in at least 20 m of water.

A series of risers (about 50) would be constructed in the last

200 m of the outfall pipe to enable the return water to be

discharged under pressure (called a diffuser).

The diffuser would be located on the seafloor, orientated at

right angles to the prevailing current direction. After initially

rising 2–5 m above the diffuser ports, the return water would

be entrained by the prevailing currents and, being denser than

the ambient seawater, fall towards the seabed. The currents,

and to a lesser degree wave action, would cause turbulent

mixing of the return water with the ambient seawater, which

would disperse the plume (see Chapter 16, Marine Environment,

for details).

construction phase

The major steps to construct the proposed desalination plant,

including the intake and outfall structures, are described below.

Construction methodThe design for the plant’s foundations would be based on the

geotechnical investigations of the site. The options include

bored piles, driven piles or strip footings, and the steps

involved in constructing the foundations include setting out,

excavation/boring, pile driving, placing reinforcing

steel/concrete and backfilling the excavated foundations.

The desalination plant would require reinforced concrete tanks

cast in situ, lined earth storages, and mechanical components

such as pumps, pressure vessels, filter elements and chemical

dosing systems. Specialised components would be imported and

assembled on-site or pre-assembled overseas and erected

on-site.

Wastes arising from construction activities would be disposed

of to local licensed landfills.

Transmission lineA new 132 kV transmission line would be installed from the

Cultana substation to the proposed desalination plant (see

Figure 5.30). This would be a double circuit transmission line of

about 25 km in length, requiring the installation of around

60 transmission towers. This is further detailed in Section 5.8.4.

Intake and outfall structuresThe method for installing the intake and outfall pipelines would

be determined during detailed design and after geotechnical

studies have determined the ease with which the pipes may be

buried along their full length. There are two main options. The

first would see the intake and outfall pipelines buried for their

full length. Alternatively, the pipelines would be buried in the

land-based sections and coastal margin and laid on the seabed

in the deeper waters.


The method to excavate the buried sections would also be

determined following detailed geotechnical studies, the two

options being:

a wheel trencher or large excavator on land and a clamshell •

bucket or cutter suction dredge operated on a temporary

jetty or flat-top barge

a combination of the above and blasting to fracture rock •

prior to removal.

Should blasting be required, it would be likely to involve

approximately 15 land-based blasts every two to three days

over a period of 40–60 days and approximately 25 underwater

blasts every two days for a period of approximately 50 days. A

maximum charge size of 10 kg would be used, and would

involve sequential detonations to minimise potential airblast,

overpressure and vibration impacts. Blasting would only occur

during daylight hours.

Testing and commissioningThere would be a commissioning period before the plant

becomes operational, during which time the plant systems

would be tested thoroughly and water quality targets would be

confirmed. During this period, the potable water produced from

the plant would not be sent to Olympic Dam; instead, it would

be combined with the return water before being discharged

through the outlet pipe into Upper Spencer Gulf.

Water supply during constructionThe coastal desalination plant would require about 100 ML of

water during the construction and commissioning phase. This

water would be sourced from the sea, if low-quality water is

required, and from the state potable water network should

higher quality water be required (for concrete manufacture,

for example).

Workforce accommodationAbout 400 people would be required during the desalination

plant construction period. Lunch rooms and basic sanitation

facilities would be established on-site for the 33 month

construction period. The workforce would stay at existing

accommodation facilities within Whyalla, and would be

transported by bus to and from the work site.

operation phase

The general operation of the desalination plant was discussed

in previous sections. Plant maintenance activities would be

undertaken during operations and would include assessing the

performance of the monitoring system, replenishing chemical

storages and visual inspections for signs of unusual wear,

corrosion or damage. The membranes used in reverse osmosis

age over time, and they become less efficient in removing salt

and impurities. These would be cleaned every few months using

agents such as acids, bases and surfactants, and the

wastewater collected would be disposed of on land in a

managed pond, where the water would evaporate and the

solids would be collected and disposed of to a licensed landfill.

Membranes typically need to be replaced after three to seven

years of operation.

chemical storage and use

Table 5.32 indicates the rate at which reagents would be used

and the storage method for the proposed desalination plant.

5.7.5 water suppLy pipeLine

overview

One water supply pipeline would be constructed to transport

potable water from the new desalination plant about 15 km

to the existing state potable water network (see following

section) and a second pipeline of about 320 km to supply water

to Olympic Dam. The South Australian government pipeline

would be buried for its entire length. The BHP Billiton pipeline

would generally be buried except where it intersects water

courses, when the pipeline would be raised above ground on

concrete plinths. In addition to the pumping stations located at

the coastal desalination plant, a further three pumping stations

would be required to transport the water to Olympic Dam. No

further pumping stations, other than the one installed within

the desalination plant, would be required for the South

Australian government pipeline to transport the water to the

existing network.

Table 5.33 presents the indicative major features of the

proposed water supply pipelines for the proposed expansion

and the South Australian government.

Figure 5.33 shows the pipeline alignment is located within or

adjacent to existing infrastructure corridors with the exception

of some areas between Point Lowly and Port Augusta. The

location and conceptual layout of proposed pumping stations

along the alignment is also shown on Figure 5.33. Figure 5.34

provides cross-sections at three indicative locations along the

corridor to show separation distances between infrastructure.

The proximity of the water supply pipeline and other linear

infrastructure to the townships of Port Augusta, Woomera and

Roxby Downs is shown in Figure 5.35.

The construction and operation of the water supply pipeline

would necessitate additional demands for water, electricity and

workforce (see Table 5.34).

south australian government water supply pipeline

New infrastructure would be required to distribute desalinated

seawater to the existing South Australian potable water

network. A new pumping station adjacent to the desalination

plant site and new pipeline approximately 15 km in length

would be required to connect the supply to the existing

Morgan–Whyalla No. 2 pipeline. A new mild steel pipeline

nominally 900 mm in diameter would be buried in a trench

within a 20 m wide easement running parallel to the new

BHP Billiton pipeline easement. The pipeline would be

constructed independently of the BHP Billiton pipeline.

In addition, a number of system alterations would be required

to allow the flow to be reversed within sections of the existing

network. Alterations to the existing South Australian potable

water supply network are subject to approvals outside of this EIS.


5

table 5.32 indicative reagent usage per annum and storage

Description usage rate (tpa)

stored volume (t)

chemical details1

storage method

Organophosphonate 100–150 20 Liquid 100% w/w Antiscalant would be stored within a bunded on-site chemical storage facility

Lime 3,500–4,600 500 Powder Lime would be stored in silos adjacent to the lime clarifier and batching tanks. Milk of lime liquid is produced and would be stored in a tank within a bunded area

Sodium hypochlorite 25 2 Liquid 10% w/w Located in bunded tanks adjacent to the intake pumping station

Hydrofluosilicic acid 200 15 Liquid 20% w/w This fluoridation agent would be stored within a bunded on-site chemical storage facility

Ammonia 25 2 Gas Ammonia gas would be stored as a liquid in pressure vessels housed within a purpose-designed building

Carbon dioxide 1,800–2,500 275 Gas Carbon dioxide gas would be stored as a liquid in pressure vessels housed within a purpose-designed building

Sulphuric acid 10,000–13,000

500 Liquid 98% w/w Acid would be stored within a bunded on-site chemical storage facility

Chlorine 200–300 40 Gas Chlorine gas would be stored in liquid form within a purpose- designed building

Sodium metabisulphite

400–500 10 Liquid 37% w/w This dechlorination agent would be stored within a bunded on-site chemical storage facility

Polyelectrolyte 90–120 15 Powder This would be stored as a powder, and batched into liquid form prior to use. It would be stored within a bunded on-site chemical storage facility

Ferric chloride 5,400–6,300 300 Liquid 42% w/w or powder

This would be stored as a powder, and batched into liquid form prior to use. It would be stored within a bunded on-site chemical storage facility. In liquid form it would be stored within a bunded tank

1 w/w = weight percent.

table 5.33 indicative major features of the proposed water supply pipelines

features proposed expansion sa government

Predominantly buried or above ground pipe Buried Buried

Length (km) 320 15

Diameter of pipeline (m) 1.4 0.9

Average width of corridor/easement (m) 40 20

Typical width of disturbance within the easement (m) 20–35 20

Approximate total length of sections above ground (km) 1.5 Nil

Depth of the excavated trench (m) 2.0–3.0 1.7–2.0

Average width of the excavated trench (m) 2.0 1.2–2.0

Total length of the trench open at any given time during construction (km)

up to 5 up to 5

Depth to top of pipeline at road crossings (m) 1 1

Maximum operating pressure (kPa) 4,000 2,500

Number of pumping stations (excluding desalination pumping station) 3 Nil

Number of pipe stacking sites 50 Nil

table 5.34 indicative major demands for the proposed water supply pipelines

expansion requirement proposed expansion sa government

Water demand during construction (ML) 485–590 n.a.

Water demand during operation (GL per annum) Negligible Negligible

Electricity consumption during operation (MWh per annum) 154,000 25,000

Peak construction/shutdown workforce 100 n.a.

Ongoing operational workforce 2 n.a.

Total land disturbance (ha) 993 30


Desalinationplant

Upper Spencer Gulf

Pimba

Whyalla

Andamooka

Roxby Downs

Port Augusta

Woomera

Point Lowly

OLYMPIC DAM

LakeMacFarlane

LakeDutton

LakeTorrens

IslandLagoon

LakeWindabout

PernattyLagoon

Pre-assemblyyard

kp80

kp60

kp40

kp20

kp320

kp300

kp280

kp260

kp240

kp220

kp200

kp180

kp160

kp140

kp120

kp100

0 10 20 30 40 50km

Passing bay

Borrow pit location


Pumping station

Landing facility





Rail alignment

Access corridor



EIS Study Area

Moomba

Whyalla

Adelaide

Port Pirie

Roxby Downs

Port Augusta

Figure 5.33 Proposed infrastructure in the southern corridor


5

OLYMPIC DAM

Roxby Downs

Port Augusta

PortPirie

Whyalla



Rail alignment

Existing Olympic DamSpecial Mining Lease

Existing Roxby DownsMunicipality

EIS Study Area

Location 1

Location 2

Location 3

LOCATION 2

70 m50 m130 m8 km160 m365 m

LOCATION 1

70 m 135 m50 m 320 m130 m

260 m 140 m 1 km 200 m 40 m 360 m 260 m

LOCATION 3

Water pipeline

Water pipeline

Santos liquid fuels pipeline

Road

Rail

Rail

132 kV transmission line

275 kV double circuittransmission line

275 kV transmission line

Cross-section location map

Existing infrastructure

Proposed infrastructure

W EViewednorth

W EViewednorth

W EViewednorth

Figure 5.34 Indicative separation distances of proposed linear infrastructure


OLYMPIC DAM

Whyalla

Port Augusta

Roxby Downs

Andamooka

LakeWindabout

PernattyLagoon

IslandLagoon

See inset 1

See inset 2

See inset 3

See inset 4

LakeTorrens

Landing facility

Desalination plant





Rail alignment

Access corridor

Residential land use



EIS Study Area

0 10 20 30 40 50km

0 1 2km

Inset 1Roxby Downs

Pre-assemblyyard

Landingfacility

Pimba intermodal facility

0 1 2km

Road/railoverpass

0 1 2km

Inset 2Woomera

Inset 3Pimba

Inset 4Port Augusta

Moomba

Whyalla

Adelaide

Port Pirie

Roxby Downs

0 1 2km

Port Augusta

Woomera

Pimba

Figure 5.35 Insets of major towns related to infrastructure within the southern corridor


5

construction phase

Construction method Vegetation along the BHP Billiton pipeline easement would be

cleared and access tracks would be constructed along the

pipeline easement to provide access for pipeline installation

equipment. Deep-rooted vegetation would be removed within a

distance of three metres either side of the mid-line of buried

pipeline sections, so as not to damage the pipe. Grass and other

shallow-rooted vegetation would be left to establish over the

easement following construction. Steel pipe sections of around

12–13.5 m long would be delivered directly to the pipeline

easement for stringing along the easement to avoid storage and

double handling. However, in some cases pipe would need to be

stored temporarily in laydown areas, termed pipe stacking sites.

These sites may occur every 5–10 km along the pipeline corridor

and would occupy an area of about 200 m x 200 m. Each site

would be cleared, grubbed and prepared with a 200 mm

compacted quarry rubble or similar base to ensure flat,

all-weather access.

The pipe would either be transported to site as a finished

product, complete with internal lining and coating, or

transported as a coated steel pipe to storage and marshalling

areas for on-site lining.

The proposed water supply pipeline would be buried about

0.5 m underground for the majority of its length. A wheel

trencher or large excavator would probably be used to dig a

2 m wide trench within the easement for the buried sections of

pipeline. The material excavated from the trench would be

stockpiled adjacent to the trench for use as backfill, with excess

material spread back over the easement. Generally around 1 km

of trench would be open at any one time for each work site,

depending on the soil types and the amount of rock through

which the trench is to be excavated. Four to five work sites may

operate at any one time and a variety of excavation methods

may be used for areas crossing watercourses, roads and major

infrastructure corridors. These would be determined by the

construction contractor and include open trenching, boring or

directional drilling.

The pipeline lengths would be lifted into the trench for jointing

using rubber ring slip joints (or similar) before being backfilled

and compacted.

Small sections of the pipeline, particularly those sections of

the line that intersect watercourses, such as the inlets to Lake

Windabout and Pernatty Lagoon, would remain above ground

(about 1.5 km in total). These above-ground sections of pipeline

would be supported on pre-cast concrete plinths or culverts to

keep the pipeline above flood levels. Above-ground pipeline

joints would be welded and the pipeline attached to the

support plinths.

Disturbed areas would be cleaned up and rehabilitated.

Measures would include removing foreign material (i.e.

construction material and waste), respreading excess material

from the excavated trench, contouring if required, and

respreading topsoil and cleared vegetation to retain the seed

bank and promote regeneration. Marker posts with visible

covers would be installed adjacent to pipeline isolation valves

and air valves to enable easy location during maintenance

works. The temporary pipe stacking sites would be

rehabilitated.

Testing and commissioning The pipeline would be hydrostatically tested for strength and

potential leaks. Once a section had been constructed it would

be filled with approximately 12–30 ML of water and the

pressure increased to exceed the anticipated operating

pressure. Generally 10–50 km long sections would be tested at

a time to 125% of operating pressure, depending on the spacing

of isolation valves. Water for each new section would usually be

drawn from the adjacent section that had been previously

tested, with make-up water added to replace the small amount

of water lost through leakage. It is anticipated that 85–90 ML

of water would be required to complete the hydrostatic testing

for the full 320 km of pipeline.

Following hydrostatic testing, the pipe would be filled

completely. This would require 400–500 ML of water sourced

from either the state potable water network or from

commissioning the desalination plant. The first flush of water

through the pipe would be of reduced quality as a result of

debris contained within the line, and so would be screened

before being sent to the process water storage dams at

Olympic Dam.

Pumping stations, substations and surge tanksIt is likely that three pumping stations would be required along

the pipeline route in addition to the main pumping station

located at the coastal desalination plant (see Figure 5.33).

These would be constructed at intervals of 50–100 km along the

pipeline and would each require an area of about 50 m x 50 m,

located adjacent to the pipeline easement and within a fenced

compound of about 1.2 ha. Concrete slab foundations would be

poured at each site and a building of about 35 m x 20 m would

be erected to house pumps and related equipment. Plant and

equipment for the pumping station are likely to be pre-

assembled in modular form and installed on-site.

An electrical substation would be constructed adjacent to each

pumping station, within the fenced compound. The electrical

substation requires an area of about 90 m x 65 m, which would

also have concrete footings for towers, pylons, disconnectors,

transformers and switch room buildings. Pads of compacted

crushed rock would be prepared for temporary buildings (e.g.

crib rooms and toilets) to be used during construction. The

plant and equipment would be manufactured off-site and

erected on-site.

The pipeline would require surge protection measures in the

form of surge tanks to release water into the pipeline during

emergency shutdown events involving the desalination plant or

any of the pumping stations. Around four surge tanks, each

with a capacity of about 200 kL, and a gravity flow tank of up


to 3.5 ML would be required along the length of the pipeline.

An area of up to 90 m x 70 m would be required for these tanks.

A concrete ring beam footing would be poured to support the

tank’s concrete or steel walls. A concrete slab floor may also be

constructed for the tank floor. The tank is likely to be covered

with a lightweight steel roof to reduce evaporation and restrict

vermin and native fauna access. Permanent fencing and gates

would be erected around the tank site boundary.

Water supply during constructionConstruction of the water supply pipeline and associated

infrastructure would require about 485–590 ML of water,

principally for the full first flush testing of the pipe following

the hydrostatic testing of sections, with small quantities also

used for dust suppression. The majority of the water would be

sourced from the commissioned Point Lowly desalination plant

or the state potable water network. Additional dust suppression

water could be drawn from purpose-drilled wells located in

local saline aquifers. All wells would be drilled and

decommissioned in accordance with applicable state legislation

and the requirements of the Department of Water, Land and

Biodiversity Conservation (DWLBC).

Workforce accommodationApproximately 100 people would be required for the

construction of the water supply pipeline. Temporary facilities,

including lunch rooms and sanitary facilities would be

constructed at each pumping station site, and mobile facilities

would be provided at the pipeline construction sites. The

workforce would be accommodated at Whyalla, Port Augusta,

Woomera and Roxby Downs. No on-site accommodation camps

would be necessary.

operation phase

Water supply pipelineThe pipeline would be operated so that pressure does not

exceed around 4,000 kPa (or PN40) at any point along the

pipeline. In general operating pressures would be 2,500 kPa

(or PN25).

Access tracks established during construction would be

maintained to allow vehicle access to the pipeline and pump-ing

stations for inspection and maintenance activities. Maintenance

and testing programs would include leak detection surveys,

ground patrols, repairing or replacing faulty pipe or other

equipment, scouring and cleaning of the pipeline and shock

chlorination.

Pumping stationsThe pumping stations would be equipped with off-site

monitoring capabilities and all water flows would be metered

and checked for accuracy. However, routine trips would occur

to undertake maintenance, including cleaning air filters for

ventilation systems, changing bearing oil, cleaning within

electrical cubicles, replacing air filters, and overhauling

equipment. Waste generated during maintenance activities

would be disposed of to a licensed landfill.

Electrical substationsThe electrical substations would be equipped with telemetry

and instrumentation to enable off-site monitoring. Maintenance

visits to the substations are likely to occur at least monthly.

During these visits, maintenance would normally be limited to

inspecting auxiliary plant such as batteries, chargers,

transformer oil levels and general housekeeping. Annual

maintenance could include functional checks of transformers,

circuit breakers and disconnectors and checks of auxiliary plant.

Surge tanksThe surge tanks would be equipped with level-measuring

equipment and telemetry to enable off-site monitoring of water

levels. The tanks would be visually inspected for leaks during

maintenance visits, which would be concurrent with visits to the

pumping station. Monthly checks may include confirming the

performance and accuracy of the level-measuring equipment

and telemetry. Annual inspections may include inspection of the

tank floor to check for build-up of sediments, and the tanks

would be drained and cleaned to remove built-up sediments if

required. The sediments would be contained and disposed of in

a licensed landfill.

5.7.6 great artesian Basin suppLy

The existing approvals for Olympic Dam include special

water licences to extract groundwater from the GAB, subject

to meeting groundwater level drawdown criteria around

the wellfield.

Potable water demand during the construction phase of on-site

or near-site infrastructure (including infrastructure within the

SML, plus potable water for the expansion of Roxby Downs,

the construction of the airport and Hiltaba Village) would be

met through the desalination of GAB water at the existing

on-site desalination plant providing the additional extraction

can maintain drawdown within approval limits.

Additional potable water, if required, would be sourced from

local saline wellfields, to be desalinated in the existing on-site

desalination plant (see Section 5.7.7). Potable water demand for

the new open pit mine and metallurgical plant, plus the

expanded Roxby Downs, new airport and Hiltaba Village would

be met from the coastal desalination plant following

construction and commissioning in around Year 4.

The existing mining and metallurgical operation would continue

to use water sourced from the GAB.

5.7.7 saLine aquifer suppLy

overview

A demand for around 50 ML/d of saline water would be

generated during the construction phase of the proposed

expansion. This demand would be met through the development

of the mine depressurisation wells and abstraction from saline

aquifers. Geological studies and drilling campaigns have been

undertaken around and within the Olympic Dam SML to identify

potential sources of saline groundwater. These investigations


5

table 5.35 indicative saline wellfield abstraction rates

saline wellfield abstraction rate (mL/d)

Open pit depressurisation wells 5–15

Motherwell Wellfield 25

Local saline wellfields 10

have indicated several potential sources of groundwater of

various qualities, which could be developed into saline

wellfields for use during the construction and operation of the

proposed expansion.

Indicative wellfield abstraction rates are shown in Table 5.35

and are further detailed in the following sections.

Depressurisation wellfield

A maximum of around 15 ML/d of saline water would be

extracted from the proposed area of the open pit during the

initial development phase, later stabilising at around 5 ML/d for

the life of the open pit mine. Details regarding this wellfield are

presented in Section 5.4.3.

motherwell wellfield

The primary saline water supply for the construction phase of

the proposed expansion would be the so-called Motherwell

Wellfield, located about 30 km north of Olympic Dam. This

wellfield intersects the upper levels of the Andamooka

limestone aquifer, and has a salinity of around 50,000 mg/L

total dissolved solids, which would be suitable for desalination

via a new on-site desalination plant.

Production from the Motherwell Wellfield would ramp -up over

time to meet the increasing saline demand during the

construction phase. This would be achieved with the installation

of additional wells. The number of wells would increase from

an initial single well, producing about 1.8 ML/d, up to 14 wells

producing around 25 ML/d within four to five years. This

capacity would be maintained for the duration of the

construction phase. Investigations of aquifer response to

the abstraction would be used to determine whether the

Motherwell Wellfield could continue operation beyond the

construction phase and become a source of low-quality water

for the operation phase.

Additional infrastructure would be required to support the

wellfield. Pipelines would be buried and would range from 0.2 m

in diameter at the most distant well, up to 0.75 m when the

production of all wells is combined. The pipelines would run

from the Motherwell Wellfield to the existing Borefield pipeline,

and then run adjacent to the existing pipeline to the existing

on-site desalination plant.

The location and a conceptual layout of the Motherwell

Wellfield and associated pipeline is presented in Figure 5.25.

Local saline wellfields

The local saline wellfields would consist of a range of wellfields

within 20 km of the existing Olympic Dam SML. These wells

would abstract water from the aquifers within the Tent Hill

geological formation (Corraberra Sandstone, Arcoona Quartzite

and Tregolana Shale – see Chapter 12, Groundwater, for further

information).

The wellfields would abstract saline-to-hypersaline water at

locations adjacent to significant infrastructure during the

construction phase, for use in civil works such as earth

compaction and dust suppression. Wellfields are proposed next

to the new TSF cells, the new metallurgical plant, the proposed

mine maintenance industrial area, Roxby Downs, Hiltaba Village

and the proposed airport (see Figure 5.25). The individual wells

would have the capacity to deliver about 0.4 ML/d each, and

total local saline wellfield abstraction would be about 16 ML/d

during the construction period. The wellfields would be

decommissioned at the end of construction activities.

5.7.8 water recycLing, reuse anD conservation

The existing Olympic Dam operation reuses water through the

following activities:

water from depressurising the underground mine, extracted •

to prevent flooding of the workings, is used in the

manufacture of CAF backfill and for dust suppression on

roadways

groundwater beneath the TSF is reclaimed for use within the •

metallurgical process

supernatant liquor from the TSF is reused within the •

metallurgical process.

The proposed mining and processing operation would increase

the reuse of water across the site by constructing infrastructure

such as the flotation tailings thickening circuit that would

create a greater demand for acidic liquor within the new

metallurgical plant. Other areas of potential water reuse and

recycling would include:

using open pit mine depressurisation water as a saline water •

source during construction of the proposed expansion

potentially using treated domestic sewage water for •

landscaping and other low-quality water uses

capturing stormwater run-off from the RSF and the open pit •

and storing it in the clay pans located between sand dunes.

Subject to the quality of the water, it would be used in dust

suppression activities or within the metallurgical plant

reducing the requirements for demineralised water in the •

proposed expanded smelter through the use of water/steam

and air/steam condensers to condense and collect excess

steam as pure water for reuse in the boilers

recycling water used for the hydrostatic testing of the water •

and gas supply pipelines as process water within the new

and existing metallurgical plants.

Documents

Description of the proposeD expansion 5...90 Olympic Dam Expansion Draft Environmental Impact Statement 2009 Coastal desalination plant (Section 5.7.4) Water supply pipeline (Section